Curable resin composition, curable resin composition tablet, molded body, semiconductor package, semiconductor component and light emitting diode

ABSTRACT

The present invention aims to provide a curable resin composition which gives a cured product having a low linear expansion coefficient. The curable resin composition of the present invention contains, as essential components, (A) an organic compound having at least two carbon-carbon double bonds reactive with SiH groups per molecule, (B) a compound containing at least two SiH groups per molecule, (C) a hydrosilylation catalyst, (D) a silicone compound having at least one carbon-carbon double bond reactive with a SiH group per molecule, and (E) an inorganic filler.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.13/638,992, filed on Oct. 2, 2012, which is a 371 of InternationalApplication No. PCT/JP2011/058407, filed on Mar. 30, 2011, which isbased upon and claims the benefit of priority from prior Japanese PatentApplication No. 2010-085900, filed on Apr. 2, 2010, Japanese PatentApplication No. 2010-085901, filed on Apr. 2, 2010, Japanese PatentApplication No. 2010-139362, filed on Jun. 18, 2010, Japanese PatentApplication No. 2010-228853, filed on Oct. 8, 2010, Japanese PatentApplication No. 2010-252977, filed on Nov. 11, 2010, Japanese PatentApplication No. 2011-013229, filed on Jan. 25, 2011, Japanese PatentApplication No. 2011-038455, filed on Feb. 24, 2011, the entire contentsof which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a curable resin composition, a curableresin composition tablet, a molded article, a semiconductor package, asemiconductor component, and a light-emitting diode.

BACKGROUND ART

Various shapes of packages containing curable resins have beenconventionally used in semiconductors. Such packages contain variousmetallic materials, which are often integrally molded with the curableresins, for the purposes such as electrically connecting thesemiconductors to the outside of the packages, maintaining the strengthof the packages, or conducting heat generated from the semiconductors tothe outside of the packages.

However, resin generally has a large linear expansion coefficient whichis not likely to be matched to the linear expansion coefficient ofmetallic materials that is generally small. For this reason, someproblems, such as warpage, peeling, cracking, and damage tosemiconductors, may occur during heat-molding, post-curing, or variousprocesses involving heating and cooling when used as semiconductorcomponents.

Regarding particularly to warpage caused by mismatch of the linearexpansion coefficients, a method of molding a curable resin evenly onboth sides of a metal has been employed to reduce the warpage.

However, since, in these days, increase in the amount of heat generatedfrom semiconductors has required a design that is excellent in heatdissipation, package designs have been introduced in which a metal to bebonded to a semiconductor element forms a bottom of the package in orderto efficiently conduct heat outside the package (Patent Literatures 1and 2).

In this case, warpage cannot be reduced by the above method, and thussolving the warpage problem is an important issue.

Some improvement of resin in terms of reduction of warpage has beenachieved by lowering the linear expansion of resin to be closer to thelinear expansion of a metal with which the resin is integrally molded,or by using a resin having a lower elastic modulus.

However, since addition of a large amount of inorganic filler in orderto lower the linear expansion reduces the fluidity of resin duringmolding, and thereby deteriorates the molding processability, such atechnique has a limitation. Moreover, a lower elastic moduluscorresponds to a reduced strength of resin, leading to loss of theprimary function of packages, that is, protection of the semiconductorelement.

For the above reasons, curable resins capable of reducing warpage insemiconductor packages have been demanded.

Meanwhile, due to the increase in heat (also light in the case wheresemiconductors are light-emitting diodes) generated from semiconductors,resins for semiconductor packages have been demanded to have higherthermal resistance (light resistance). In response to such demand, someresins which have high thermal resistance and are cured byhydrosilylation reaction have been employed as resins for semiconductorpackages (Patent Literatures 1 and 3).

CITATION LIST Patent Literature

Patent Literature 1: JP-A 2010-62272

Patent Literature 2: JP-A 2009-302241

Patent Literature 3: JP-A 2005-146191

SUMMARY OF INVENTION Technical Problem

In this context, the present invention aims to provide a curable resincomposition which gives a cured product having a low linear expansioncoefficient. The present invention also aims to provide a semiconductorpackage which is formed by integrally molding the curable resincomposition and a metal, and has reduced warpage, and also to provide asemiconductor produced by using the semiconductor package.

Solution to Problem

The present inventors have made intensive studies to solve the aboveproblems. As a result, they have found that a curable resin compositioncontaining, as essential components, (A) an organic compound having atleast two carbon-carbon double bonds reactive with SiH groups permolecule, (B) a compound containing at least two SiH groups permolecule, (C) a hydrosilylation catalyst, (D) a silicone compound havingat least one carbon-carbon double bond reactive with a SiH group permolecule, and (E) an inorganic filler can solve the above problems,thereby completing the present invention.

Namely, the present invention relates to the following features:

(1) a curable resin composition containing, as essential components,

(A) an organic compound having at least two carbon-carbon double bondsreactive with SiH groups per molecule,

(B) a compound containing at least two SiH groups per molecule,

(C) a hydrosilylation catalyst,

(D) a silicone compound having at least one carbon-carbon double bondreactive with a SiH group per molecule, and

(E) an inorganic filler;

(2) the curable resin composition according to the above (1), whereinthe component (D) is a linear polysiloxane containing a vinyl group at aterminal thereof;

(3) the curable resin composition according to the above (1) or (2),wherein the component (D) has a weight average molecular weight of atleast 1,000 but not more than 1,000,000;

(4) the curable resin composition according to any one of the above (1)to (3), wherein the component (E) is spherical silica;

(5) the curable resin composition according to any one of the above (1)to (4), further containing (F) a white pigment;

(6) the curable resin composition according to the above (5), whereinthe component (F) has an average particle size of 1.0 μm or less;

(7) the curable resin composition according to the above (5) or (6),wherein the component (F) is titanium oxide;

(8) the curable resin composition according to the above (7), whereinthe component (F) is titanium oxide that is surface-treated with anorganosiloxane;

(9) the curable resin composition according to the above (7), whereinthe component (F) is titanium oxide that is surface-treated with aninorganic compound;

(10) the curable resin composition according to the above (9), whereinthe component (F) is surface-treated with an aluminum compound;

(11) the curable resin composition according to the above (5) or (6),wherein the component (F) is at least one selected from the groupconsisting of zinc oxide, zirconium oxide, strontium oxide, niobiumoxide, boron nitride, barium titanate, and barium sulfate;

(12) the curable resin composition according to any one of the above (1)to (11), further containing (G) a metal soap;

(13) the curable resin composition according to the above (12), whereinthe component (G) is a metal stearate;

(14) the curable resin composition according to the above (13), whereinthe component (G) is at least one selected from the group consisting ofcalcium stearate, magnesium stearate, zinc stearate, and aluminumstearate;

(15) the curable resin composition according to any one of the above (1)to (14), wherein the component (D) is contained in an amount of 30% byweight or more of the total weight of the component (A) and thecomponent (B);

(16) the curable resin composition according to any one of the above (1)to (15), wherein the component (E) is contained in a total amount of 70%by weight or more of the whole curable resin composition;

(17) the curable resin composition according to any one of the above (5)to (16), wherein the component (F) is contained in an amount of 10% byweight or more of the whole curable resin composition;

(18) the curable resin composition according to any one of the above(12) to (17), wherein the component (G) is contained in an amount of0.01% to 5% by weight of the whole curable resin composition;

(19) the curable resin composition according to any one of the above (1)to (18), wherein a cured product of the curable resin composition has aspectral reflectance of 80R % or more at 420 nm, 440 nm, and 460 nm, andhas a spectral reflectance retention rate ([spectral reflectance afterthermal resistance test]/[initial spectral reflectance]×100) of 90% ormore after a thermal resistance test at a temperature of 180° C. for 72hours;

(20) the curable resin composition according to any one of the above (1)to (19), wherein a surface of a molded article formed by curing thecurable resin composition has a light reflectance at a wavelength of 470nm of 90% or more;

(21) the curable resin composition according to any one of the above (1)to (20), wherein when the curable resin composition is molded on onesurface of a lead frame for light-emitting diodes to form a package, awarpage of the package is at most ±1.0 mm;

(22) the curable resin composition according to any one of the above (1)to (21), for use in a semiconductor package;

(23) a curable resin composition tablet including the curable resincomposition according to any one of the above (1) to (22) that contains(F) a white pigment as an essential component, wherein at least one ofthe component (A) and the component (B) is a liquid having a viscosityof at most 50 Pa·s at a temperature of 23° C.,

the component (E) and the component (F) are contained in a total amountof 70% to 95% by weight, and

particles having a size of 12 μm or less account for 40% by volume ormore of the total of the component (E) and the component (F);

(24) a molded article formed by curing the curable resin compositionaccording to any one of the above (1) to (21), wherein a surface of themolded article has a light reflectance at a wavelength of 470 nm of 90%or more;

(25) a semiconductor package formed by molding the curable resincomposition according to the above (22);

(26) a semiconductor package formed by integrally molding the curableresin composition according to the above (22) and a metal;

(27) the semiconductor package according to the above (25) or (26),wherein the curable resin composition and a lead frame are integrallymolded by transfer molding;

(28) the semiconductor package according to any one of the above (25) to(27), wherein the semiconductor package substantially includes a metaland a resin formed on one surface of the metal;

(29) a semiconductor package formed by transfer molding the curableresin composition according to the above (22);

(30) a semiconductor component produced by using the semiconductorpackage according to any one of the above (25) to (29); and

(31) a light-emitting diode produced by using the semiconductor packageaccording to any one of the above (25) to (29).

Advantageous Effects of Invention

The curable resin composition of the present invention provides acurable resin composition which gives a cured product having a lowlinear expansion coefficient. Therefore, provided are a semiconductorpackage which is produced by integrally molding the curable resincomposition and a metal and has reduced warpage, and a semiconductorproduced by using the semiconductor package.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing initial reflectances at various wavelengths.

FIG. 2 is a diagram showing reflectances at various wavelengths after athermal resistance test.

FIG. 3 is a conceptual diagram of a molded article.

FIG. 4 is a schematic diagram showing a method of measuring thestrength.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described in detail.

The curable resin composition of the present invention contains, asessential components,

(A) an organic compound having at least two carbon-carbon double bondsreactive with SiH groups per molecule,

(B) a compound containing at least two SiH groups per molecule,

(C) a hydrosilylation catalyst,

(D) a silicone compound having at least one carbon-carbon double bondreactive with a SiH group per molecule, and

(E) an inorganic filler.

The components are explained below.

(Component (A))

The component (A) is not particularly limited, as long as it is anorganic compound having at least two carbon-carbon double bonds reactivewith SiH groups per molecule.

(Skeleton of Component (A))

Preferably, the organic compound is not a compound containing a siloxaneunit (Si—O—Si) such as polysiloxane-organic block copolymers andpolysiloxane-organic graft copolymers, and does not contain elementsother than C, H, N, O, S, and halogens as constituent elements.

Compounds containing a siloxane unit disadvantageously tend to lead tolow adhesion of the semiconductor package to a lead frame or a sealingresin.

Organic compounds as the component (A) are classified into organicpolymeric compounds and organic monomeric compounds.

(Examples of Polymeric Component (A))

Examples of the component (A) which is an organic polymer includeorganic polymeric compounds having a polyether skeleton, a polyesterskeleton, a polyarylate skeleton, a polycarbonate skeleton, a saturatedhydrocarbon skeleton, a unsaturated hydrocarbon skeleton, a polyacrylicacid ester skeleton, a polyamide skeleton, a phenol-formaldehyde (phenolresin) skeleton, and a polyimide skeleton.

Specifically, examples of the polyether polymer include polyoxyethylene,polyoxypropylene, polyoxytetramethylene, andpolyoxyethylene-polyoxypropylene copolymers. More specific examplesthereof include compounds represented by the following formula:

wherein R¹ and R² each represent a C1 to C6 bivalent organic group notcontaining elements other than C, H, N, O, S, and halogens asconstituent elements; and n, m, and 1 each represent a number of 1 to300.

Examples of other polymers include polyester polymers obtained bycondensation of a dibasic acid such as adipic acid, phthalic acid,isophthalic acid, terephthalic acid, and hexahydrophthalic acid, and aglycol such as ethylene glycol, diethylene glycol, propylene glycol,tetramethylene glycol, and neopentyl glycol, or by ring-openingpolymerization of lactones; ethylene-propylene copolymers,polyisobutylene, copolymers of isobutylene and isoprene or the like,polychloroprene, polyisoprene, copolymers of isoprene and butadiene,acrylonitrile, styrene or the like, polybutadiene, copolymers ofbutadiene and styrene, acrylonitrile or the like, polyisoprene,polybutadiene, polyolefin polymers (saturated hydrocarbon polymers)obtained by hydrogenation of copolymers of isoprene or butadiene andacrylonitrile, styrene or the like; polyacrylic acid esters obtained byradical polymerization of monomers such as ethyl acrylate and butylacrylate; acrylic acid ester copolymers of an acrylic acid ester such asethyl acrylate and butyl acrylate and vinyl acetate, acrylonitrile,methyl metacrylate, styrene or the like; graft polymers obtained bypolymerization of vinyl monomers in the presence of the above organicpolymers; polysulfide polymers, polyamide polymers such as nylon 6produced by ring-opening polymerization of ε-aminocaprolactam, nylon 66produced by polycondensation of hexamethylenediamine and adipic acid,nylon 610 produced by polycondensation of hexamethylenediamine andsebacic acid, nylon 11 produced by polycondensation of ε-aminoundecanoicacid, nylon 12 produced by ring-opening polymerization ofε-aminolaurolactam, and copolymer nylons derived from two or more kindsof the aforementioned nylons; polycarbonate polymers produced by, forexample, polycondensation of bisphenol A and carbonyl chloride; diallylphthalate polymers; and polymers having a phenol-formaldehyde (phenolresin) skeleton such as novolac phenol resin, resol phenol resin,ammonia-resol phenol resin, and benzylic ether phenol resin.

The component (A) can be prepared by introducing an alkenyl group havinga carbon-carbon double bond into any of the polymer skeletons.

In this case, the alkenyl group having a carbon-carbon double bond maybe located at any part of the molecule but is preferably located at aside chain or at a terminal in view of reactivity.

Various proposed methods may be employed for introducing an alkenylgroup into the polymer skeleton. Such methods are classified roughlyinto methods of introducing an alkenyl group after polymerization andmethods of introducing an alkenyl group during polymerization.

For example, the methods of introducing an alkenyl group afterpolymerization include allowing an organic polymer containing afunctional group such as a hydroxyl group, an alkoxide group, a carboxylgroup, and an epoxy group at a terminal, a main chain, or a side chainto react with an organic compound containing both an active groupreactive with the functional group and an alkenyl group so that thealkenyl group is introduced into the terminal, main chain, or sidechain. Examples of the organic compound having both an active groupreactive with the functional group and an alkenyl group include C3-C20unsaturated fatty acids, acid halides, acid anhydrides and the like,such as acrylic acid, methacrylic acid, vinyl acetate, acrylic acidchloride, and acrylic acid bromide; C3-C20 unsaturated aliphaticalcohol-substituted carbonic acid halides such as allyl chloroformate(CH₂═CHCH₂OCOCl) and allyl bromoformate (CH₂═CHCH₂OCOBr); allylchloride, allyl bromide, vinyl(chloromethyl)benzene,allyl(chloromethyl)benzene, allyl(bromomethyl)benzene,allyl(chloromethyl)ether, allyl(chloromethoxy)benzene,1-butenyl(chloromethyl)ether, 1-hexenyl(chloromethoxy)benzene,allyloxy(chloromethyl)benzene, and allyl isocyanate.

Moreover, a method of introducing an alkenyl group bytransesterification may be employed. This method includestransesterifying an alcohol residue in an ester moiety of a polyesterresin or acrylic resin with an alkenyl-containing alcohol or analkenyl-containing phenol derivative in the presence of atransesterification catalyst. The alkenyl-containing alcohol oralkenyl-containing phenol derivative to be used for transesterificationof the alcohol residue is not limited as long as it is an alcohol orphenol derivative that has at least one alkenyl group and at least onehydroxyl group, preferably one hydroxyl group. Although the catalyst isnot necessarily used, titanium catalysts and tin catalysts arepreferred.

Examples of such a compound include vinyl alcohol, allyl alcohol,3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 6-hepten-1-ol, 7-octen-1-ol,8-nonen-1-ol, 9-decen-1-ol, 2-(allyloxy)ethanol, neopentyl glycolmonoallyl ether, glycerol diallyl ether, trimethylol propane triallylether, trimethylol ethane triallyl ether, pentaerythritol tetraallylether, 1,2,6-hexanetriol triallyl ether, sorbitan triallyl ether, andcompounds represented by the following formulae:

and the like. In view of easy availability, among the above examples,allyl alcohol, vinyl alcohol, 3-buten-1-ol, 2-(allyloxy)ethanol, andcompounds represented by the following formulae:

are preferred.

Moreover, another method of introducing an alkenyl group may bementioned in which an ester moiety of a polyester resin or acrylic resinis transesterified with an esterified product (e.g. an acetic acidester) of the above alcohol or phenol derivative in the presence of atransesterification catalyst, while a generated low molecular weightesterified product (e.g. an acetic acid ester) of the alcohol residue inthe ester moiety of the polyester resin or acrylic resin is removedoutside the system by vacuum distillation or the like.

Furthermore, it is also possible to introduce an alkenyl group into theterminal by a method including living polymerization ofmethyl(meth)acrylate or the like and subsequent termination of theliving terminal with a compound containing an alkenyl group.

Examples of the method of introducing an alkenyl group duringpolymerization include, in the case of producing an organic polymerskeleton of the component (A) used in the present invention by radicalpolymerization, introduction of an alkenyl group into a side chain or aterminal of the organic polymer skeleton by using a vinyl monomer thatcontains an alkenyl group having low radical reactivity in the molecule,such as allyl methacrylate and allyl acrylate, or a radical chaintransfer agent that contains an alkenyl group having low radicalreactivity, such as allyl mercaptan.

The component (A) preferably has any molecular weight in the range of100 to 100,000 although the molecular weight is not particularlylimited. In the case where the component (A) is an organic polymercontaining an alkenyl group, the molecular weight is particularlypreferably in the range of 500 to 20,000. The molecular weight of 500 orless is less likely to lead to characteristics resulting from the use ofan organic polymer, such as imparting of flexibility. The molecularweight of 100,000 or more is less likely to lead to an effect ofcrosslinking by a reaction between an alkenyl group and a SiH group.

(Examples of Monomeric Component (A))

Examples of the component (A) which is an organic monomer include phenolcompounds, bisphenol compounds, aromatic hydrocarbon compounds such asbenzene and naphthalene; aliphatic hydrocarbon compounds (e.g. linear,alicyclic compounds); heterocyclic compounds; and mixtures thereof.

(Carbon-Carbon Double Bond in Component (A))

The bonding sites of the carbon-carbon double bonds reactive with SiHgroups are not particularly limited, and may be located at any part ofthe molecule.

The carbon-carbon double bonds reactive with SiH groups in the component(A) are not particularly limited, and groups represented by thefollowing formula (I):

(wherein R¹ represents a hydrogen atom or a methyl group) are preferredin view of reactivity. In view of easy availability of materials, groupsrepresented by the following formula:

are particularly preferred.

Preferred examples of the carbon-carbon double bonds reactive with SiHgroups in the component (A) include alicyclic groups represented by thefollowing formula (II):

(wherein R² represents a hydrogen atom or a methyl group) in terms ofhigh thermal resistance of the cured product. Moreover, in view of easyavailability of materials, alicyclic groups represented by the followingformula:

are particularly preferred.(Bonding Group Between Carbon-Carbon Double Bond and Skeleton inComponent (A))

The carbon-carbon double bonds reactive with SiH groups may be directlybonded to a skeletal portion of the component (A), or may be covalentlybonded thereto via a bivalent or higher valent substituent. The bivalentor higher valent substituent is not particularly limited as long as thesubstituent has a carbon number of 0 to 10. Preferably, the substituentdoes not contain elements other than C, H, N, O, S, and halogens asconstituent elements. As examples of such a substituent, thoserepresented by the following formulae:

may be mentioned. Moreover, two or more of these bivalent or highervalent substituents may be covalently bonded to form one bivalent orhigher valent substituent.

As the group to be covalently bonded to the skeletal portion mentionedabove, specifically, a vinyl group, allyl group, methallyl group, acrylgroup, methacryl group, 2-hydroxy-3-(allyloxy)propyl group,2-allylphenyl group, 3-allylphenyl group, 4-allylphenyl group,2-(allyloxy)phenyl group, 3-(allyloxy)phenyl group, 4-(allyloxy)phenylgroup, 2-(allyloxy)ethyl group, 2,2-bis(allyloxymethyl)butyl group,3-allyloxy-2,2-bis(allyloxymethyl)propyl group, and groups representedby the following formulae:

may be mentioned.(Specific Examples of Component (A))

Specific examples of the organic polymeric component (A) include1,2-polybutadiene (with a 1.2 ratio of 10% to 100%, preferably of 50% to1000), allyl ether of novolac phenol, allylated polyphenylene oxide, andthose represented by the following formulae:

wherein R¹ represents H or CH₃; R² and R³ each represent a C1 to C6bivalent organic group not containing elements other than C, H, N, O, S,and halogens as constituent elements; X and Y each represent a C0 to C10bivalent substituent; and n, m, and 1 each represent a number of 1 to300,

wherein R¹ represents H or CH₃; R⁴ and R⁵ each represent a C1 to C6bivalent organic group; X and Y each represent a C0 to C10 bivalentsubstituent; and n, m, and 1 each represent a number of 1 to 300,

wherein R¹ represents H or CH₃; R⁶ and R⁷ each represent a C1 to C20bivalent organic group; X and Y each represent a C0 to C10 bivalentsubstituent; and n, m, and 1 each represent a number of 1 to 300,

wherein R¹ represents H or CH₃; R⁸ and R⁹ each represent a C1 to C6bivalent organic group; X and Y each represent a C0 to C10 bivalentsubstituent; and n, m, and 1 each represent a number of 1 to 300,

wherein R¹ represents H or CH₃; R¹⁰, R¹¹, and R¹² each represent a C1 toC6 bivalent organic group; X and Y each represent a C0 to C10 bivalentsubstituent; and n, m, 1, and p each represent a number of 1 to 300.

Specific examples of the organic monomeric component (A) include diallylphthalate, triallyl trimellitate, diethylene glycol bisallyl carbonate,trimethylolpropane diallyl ether, pentaerythritol triallyl ether,1,1,2,2-tetraallyloxyethane, diallylidenepentaerythritol, triallylcyanurate, triallyl isocyanurate, 1,2,4-trivinylcyclohexane,divinylbenzenes (with a purity of 50 to 100%, preferably of 80 to 100%),divinylbiphenyl, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, andoligomers thereof, and compounds represented by the following formulae:

Moreover, compounds obtained by allyl group substitution for part or allof glycidyl groups in known epoxy resin, and the like may also bementioned.

Also usable as the component (A) are low molecular weight compoundswhich are difficult to express dividedly in terms of the skeletalportion and alkenyl groups as described above. Specific examples of thelow molecular weight compounds include aliphatic acyclic polyenecompounds such as butadiene, isoprene, octadiene and decadiene;alicyclic polyene compounds such as cyclopentadiene, cyclohexadiene,cyclooctadiene, dicyclopentadiene, tricyclopentadiene and norbornadiene;substituted alicyclic olefin compounds such as vinylcyclopentene andvinylcyclohexene, and the like.

(Preferred Requirements for Component (A))

In view of the possibility of further improvement in thermal resistance,the component (A) preferably has carbon-carbon double bonds reactivewith SiH groups in an amount of not less than 0.001 mol, more preferablynot less than 0.005 mol, and still more preferably not less than 0.008mol, per gram of the component (A).

The number of carbon-carbon double bonds reactive with SiH groups in thecomponent (A) is not limited as long as the number is at least two permolecule on average. For achieving further improvement in mechanicalstrength, the number is preferably more than two, and more preferablynot less than three. If the number of carbon-carbon double bondsreactive with SiH groups in the component (A) is one or less permolecule, the component (A), after the reaction with the component (B),only gives a graft structure and fails to give a crosslinked structure.

In view of good reactivity, the component (A) preferably contains atleast one vinyl group, and more preferably at least two vinyl groups,per molecule. It preferably contains at most six vinyl groups, and morepreferably at most four vinyl groups, per molecule because the storagestability then tends to be better.

In view of high mechanical thermal resistance, of less stringiness, goodmoldability and handleability of the material liquid, of easyhomogeneous mixing with powders such as the component (E) and thecomponent (F), and of good moldability in the form of curable resincomposition tablets, the component (A) preferably has a molecular weightof less than 900, more preferably less than 700, and still morepreferably less than 500.

In order to achieve homogeneous mixing with other components and goodworkability, the component (A) preferably has a viscosity of lower than1000 poise, more preferably lower than 300 poise, and still morepreferably lower than 30 poise, at a temperature of 23° C. The viscositycan be determined using an E-type viscometer.

In view of higher light resistance, the component (A) is preferably lowin the amount of compounds containing a phenolic hydroxyl group and/or aderivative of a phenolic hydroxyl group, and is more preferably freefrom compounds containing a phenolic hydroxyl group and/or a derivativeof a phenolic hydroxyl group. The term “phenolic hydroxyl group” hereinmeans a hydroxyl group directly bound to an aromatic hydrocarbon nucleussuch as, for example, a benzene ring, a naphthalene ring or ananthracene ring. The term “derivative of a phenolic hydroxyl group”means a group resulting from substitution of the hydrogen atom of thephenolic hydroxyl group with an alkyl group (e.g. a methyl group, anethyl group), an alkenyl group (e.g. a vinyl group, an allyl group), anacyl group (e.g. an acetoxy group), or the like.

In view of particularly good light resistance, the weight ratio ofaromatic rings in the component (A) is preferably not more than 50% byweight, more preferably not more than 40% by weight, and still morepreferably not more than 30% by weight. Most preferably, the component(A) does not contain any aromatic hydrocarbon ring.

In view of less coloring and high light resistance of a cured product tobe obtained, the component (A) is preferably vinylcyclohexene,dicyclopentadiene, vinyl norbornene, triallyl isocyanurate, diallylether of 2,2-bis(4-hydroxycyclohexyl)propane, or1,2,4-trivinylcyclohexane, and is particularly preferably triallylisocyanurate, diallyl ether of 2,2-bis(4-hydroxycyclohexyl)propane, or1,2,4-trivinylcyclohexane.

(Preferred Structure 1 of Component (A))

In view of particularly high thermal resistance and light resistance,the component (A) is preferably a compound represented by the followingformula (III):

wherein R¹s each represent a monovalent organic group containing 1 to 50carbon atoms, and they may be the same or different from one another.

In view of higher thermal resistance of a cured product to be obtained,R¹s in the formula (III) each are preferably a monovalent organic groupcontaining 1 to 20 carbon atoms, more preferably a monovalent organicgroup containing 1 to 10 carbon atoms, and still more preferably amonovalent organic group containing 1 to 4 carbon atoms. As preferredexamples of these R¹s, a methyl group, ethyl group, propyl group, butylgroup, phenyl group, benzyl group, phenethyl group, vinyl group, allylgroup, glycidyl group, and groups of the following formulae:

and the like are mentioned.

In view of the possibility of good adhesion of the package to a leadframe or a sealing agent, or of the possibility of high mechanicalstrength of the resulting package, at least one of the three R¹s ispreferably a monovalent C1-C50 organic group containing at least oneepoxy group, and is more preferably a monovalent C1-C50 organic groupcontaining at least one epoxy group represented by the followingformula.

Preferred examples of such R¹s include a glycidyl group, and groupsrepresented by the following formulae:

and the like.

In view of the possibility of good heat resistance of a cured product tobe obtained, R¹s in the formula (III) each are preferably a monovalentC1-C50 organic group having at most two oxygen atoms and containingexclusively C, H, and O as constituent elements, and more preferably amonovalent C1-C50 hydrocarbon group. Preferred examples of these R¹sinclude a methyl group, ethyl group, propyl group, butyl group, phenylgroup, benzyl group, phenethyl group, vinyl group, allyl group, glycidylgroup, and groups represented by the following formulae:

and the like.

In view of good reactivity, at least one of the three R¹s in the formula(III) is preferably a monovalent C1-C50 organic group containing atleast one group represented by the following formula:

and is more preferably a monovalent C1-C50 organic group containing atleast one group represented by the following formula (IV):

wherein R² represents a hydrogen atom or a methyl group. Still morepreferred are organic compounds in which at least two of the three R¹sare represented by the following formula (V):

(wherein R³ represents a direct bond or a bivalent organic group having1 to 48 carbon atoms, and R⁴ represents a hydrogen atom or a methylgroup), a plurality of R³s may be the same or different, and a pluralityof R⁴s may be the same or different.

R³ in the formula (V) is a direct bond or a bivalent organic grouphaving 1 to 48 carbon atoms. In view of higher thermal resistance of apackage to be obtained, the R³ is preferably a direct bond or a bivalentorganic group having 1 to 20 carbon atoms, more preferably a direct bondor a bivalent organic group having 1 to 10 carbon atoms, and still morepreferably a direct bond or a bivalent organic group having 1 to 4carbon atoms. Preferred examples of such R³ include groups representedby the following formulae:

and the like.

In view of the possibility of good thermal resistance of a package to beobtained, R³ in the formula (V) is preferably a direct bond, or abivalent C1-C48 organic group having at most two oxygen atoms andcontaining exclusively C, H, and O as constituent elements. Morepreferably, the R³ is a direct bond, or a bivalent C1-C48 hydrocarbongroup. Preferred examples of such R³ include groups represented by thefollowing formulae:

and the like.

R⁴ in the formula (V) is a hydrogen atom or a methyl group. In view ofgood reactivity, the R⁴ is preferably a hydrogen atom.

However, the preferred examples of the organic compound represented bythe formula (III) each need to have at least two carbon-carbon doublebonds reactive with SiH groups per molecule. In view of the possibilityof further improvement in thermal resistance, more preferred are organiccompounds having at least three carbon-carbon double bonds reactive withSiH groups per molecule.

Preferred specific examples of such organic compounds represented by theformula (III) include triallyl isocyanurate, and compounds representedby the following formulae:

and the like.(Preferred Structure 2 of Component (A))

In view of good compatibility with the component (B), and of lowvolatility of the component (A) leading to less possibility of causingoutgassing from a package to be obtained, reaction products of one ormore kinds of compounds selected from the organic compounds having atleast two carbon-carbon double bonds reactive with SiH groups permolecule as mentioned as examples of the component (A), with a compound(β) containing a SiH group are also preferred.

(Component (β)

The component (β) is a compound containing a SiH group, and examplesthereof include acyclic and/or cyclic polyorganosiloxanes containing aSiH group.

Specific examples thereof include compounds represented by the followingformulae:

and the like.

In view of better compatibility with the organic compounds having atleast two carbon-carbon double bonds reactive with SiH groups permolecule, the component (β) is preferably a cyclic polyorganosiloxanecontaining at least three SiH groups per molecule, represented by thefollowing formula (VI):

wherein R¹ represents an organic group having 1 to 6 carbon atoms, and nrepresents a number of 3 to 10.

The substituent R¹ in the compound represented by the formula (VI)preferably does not contain constituent elements other than C, H, and O.The R¹ is more preferably a hydrocarbon group, and still more preferablya methyl group.

In view of easy availability and the like,1,3,5,7-tetramethylcyclotetrasiloxane is preferred.

Other examples of the component (β) include compounds containing a SiHgroup, such as bisdimethylsilylbenzene.

The components (β) as mentioned above may be used alone, or two or morekinds thereof may be used in admixture.

(Reaction Between Organic Compound Having at Least Two Carbon-CarbonDouble Bonds Reactive with SiH Groups Per Molecule, and Component (β))

The following description will discuss a hydrosilylation reactionbetween the organic compound having at least two carbon-carbon doublebonds reactive with SiH groups per molecule and the component (β) in thecase where a compound obtainable by a hydrosilylation reaction betweenthe organic compound having at least two carbon-carbon double bondsreactive with SiH groups per molecule and the component (β) is used asthe component (A) in the present invention.

Here, the hydrosilylation reaction between the organic compound havingat least two carbon-carbon double bonds reactive with SiH groups permolecule and the component (β) may give a mixture of a plurality ofcompounds including the component (A) in the present invention. In thiscase, the curable resin composition of the present invention can beprepared by using the mixture as it is without separating the component(A).

In the case of subjecting the organic compound having at least twocarbon-carbon double bonds reactive with SiH groups per molecule and thecomponent (β) to a hydrosilylation reaction, the mixing ratio of theorganic compound having at least two carbon-carbon double bonds reactivewith SiH groups per molecule and the component (β) is not particularlylimited. Because gelation during the reaction can be suppressed,generally, the total number (X) of carbon-carbon double bonds reactivewith SiH groups in the organic compound having at least twocarbon-carbon double bonds reactive with SiH groups per molecule to bemixed, and the total number (Y) of SiH groups in the component (β) to bemixed preferably satisfy the ratio: X/Y≧2, and more preferably satisfythe ratio: X/Y≧3. In view of better compatibility between the component(A) and the component (B), the X and Y preferably satisfy the ratio:10≧X/Y, and more preferably satisfy the ratio: 5≧X/Y.

In the case of subjecting the organic compound having at least twocarbon-carbon double bonds reactive with SiH groups per molecule and thecomponent (β) to a hydrosilylation reaction, an appropriate catalyst maybe used. The following may be used as the catalyst: a simple substanceof platinum; solid platinum supported by a carrier such as alumina,silica, and carbon black; chloroplatinic acid; complexes ofchloroplatinic acid with an alcohol, aldehyde, ketone, or the like;platinum-olefin complexes (e.g., Pt(CH₂═CH₂)₂(PPh₃)₂, Pt(CH₂═CH₂)₂Cl₂),platinum-vinylsiloxane complexes (e.g., Pt(ViMe₂SiOSiMe₂Vi)_(n),Pt[(MeViSiO)₄]_(m)), platinum-phosphine complexes (e.g., Pt(PPh₃)₄,Pt(PBu₃)₄), platinum-phosphite complexes (e.g., Pt[P(OPh)₃]₄,Pt[P(OBu)₃]₄) (in those formulae, Me is a methyl group, Bu is a butylgroup, Vi is a vinyl group, Ph is a phenyl group, and n and m areintegers); dicarbonyldichloroplatinum; Karstedt catalysts;platinum-hydrocarbon complexes described in Ashby's U.S. Pat. Nos.3,159,601 and 3,159,662; and platinum alcoholate catalysts described inLamoreaux's U.S. Pat. No. 3,220,972. In addition, platinumchloride-olefin complexes described in Modic's U.S. Pat. No. 3,516,946are also usable in the present invention.

Other examples of the catalyst except platinum compounds includeRhCl(PPh)₃, RhCl₃, RhAl₂O₃, RuCl₃, IrCl₃, FeCl₃, PdCl₂.2H₂O, NiCl₂, andTiCl₄.

In view of catalytic activity, chloroplatinic acid, platinum-olefincomplexes, platinum-vinylsiloxane complexes, and the like are preferredamong the above examples. These catalysts may be used alone, or two ormore kinds thereof may be used in combination.

The amount of the catalyst added is not particularly limited. Forachieving sufficient curing and keeping the costs of the curable resincomposition relatively low, the minimum amount is preferably 10⁻⁸ mol,and more preferably 10⁻⁶ mol, per mol of SiH groups in the component(β). The maximum amount is preferably 10⁻¹ mol, and more preferably 10⁻²mol, per mol of SiH groups in the component (β).

A promoter may be used along with the catalyst. Examples of the promoterinclude phosphorus compounds such as triphenylphosphine; 1,2-diestercompounds such as dimethyl maleate; acetylene alcohol compounds such as2-hydroxy-2-methyl-1-butyne; sulfur compounds such as a simple substanceof sulfur; and amine compounds such as triethylamine. The amount of thepromoter added is not particularly limited, but the minimum amount ispreferably 10⁻² mol, and more preferably 10⁻¹ mol, and the maximumamount is preferably 10⁻² mol, and more preferably 10 mol, per mol ofthe hydrosilylation catalyst.

Various methods may be employed for mixing the organic compound havingat least two carbon-carbon double bonds reactive with SiH groups permolecule, the component (β), and the catalyst for reaction. Preferred isa method of preliminarily mixing the organic compound having at leasttwo carbon-carbon double bonds reactive with SiH groups per moleculewith the catalyst, and then mixing the mixture with the component (β). Amethod of adding the catalyst to a mixture of the organic compoundhaving at least two carbon-carbon double bonds reactive with SiH groupsper molecule and the component (β) leads to difficulty in controllingthe reaction. In the case of a method of adding the organic compoundhaving at least two carbon-carbon double bonds reactive with SiH groupsper molecule to a mixture of the component (β) and the catalyst, thecomponent (β) may be altered because the component (β) can react withexisting moisture in the presence of the catalyst.

Various temperatures may be employed for the reaction. The lower limitof the temperature range is preferably 30° C., and more preferably 50°C., and the upper limit of the temperature range is preferably 200° C.,and more preferably 150° C. in the reaction. Low reaction temperaturesprolong the time for sufficient reaction, and high reaction temperaturesare not practical. The reaction may be performed at a constanttemperature, or may be performed while the temperature is changed inmultiple steps or continuously as needed.

Various reaction times and various pressures during the reaction may beemployed as needed.

A solvent may be used in the hydrosilylation reaction. The usablesolvent is not particularly limited as long as it does not inhibit thehydrosilylation reaction. Specifically, suitable examples of the solventinclude hydrocarbon solvents such as benzene, toluene, hexane, andheptane; ether solvents such as tetrahydrofuran, 1,4-dioxane,1,3-dioxolane, and diethyl ether; ketone solvents such as acetone, andmethyl ethyl ketone; and halogen solvents such as chloroform, methylenechloride, and 1,2-dichloroethane. A mixed solvent containing two or moresolvents may be used as the solvent. Toluene, tetrahydrofuran,1,3-dioxolane, and chloroform are preferred as the solvent. The amountof the solvent to be used may be appropriately set.

Various other additives may be used in order to, for example, controlthe reactivity.

After the reaction between the organic compound having at least twocarbon-carbon double bonds reactive with SiH groups per molecule and thecomponent (β), the solvent or/and the unreacted organic compound havingat least two carbon-carbon double bonds reactive with SiH groups permolecule or/and component (β) may be removed. By removing thesevolatiles, the resulting component (A) does not contain any volatiles sothat problems of voids and cracks caused by volatilization of volatilesare less likely to occur during curing with the component (B). Examplesof the removal method include vacuum distillation, and treatment withactivated carbon, aluminum silicate, silica gel, or the like. The vacuumdistillation is preferably performed at low temperatures. In this case,the upper limit of the temperature is preferably 100° C., and morepreferably 60° C. Treatment at high temperatures tends to lead toalteration such as thickening.

Examples of the component (A) that is a reaction product of the organiccompound having at least two carbon-carbon double bonds reactive withSiH groups per molecule and the component (β) as mentioned above includea reaction product of bisphenol A diallyl ether and1,3,5,7-tetramethylcyclotetrasiloxane, a reaction product ofvinylcyclohexene and 1,3,5,7-tetramethylcyclotetrasiloxane, a reactionproduct of divinylbenzene and 1,3,5,7-tetramethylcyclotetrasiloxane, areaction product of dicyclopentadiene and1,3,5,7-tetramethylcyclotetrasiloxane, a reaction product of triallylisocyanurate and 1,3,5,7-tetramethylcyclotetrasiloxane, a reactionproduct of diallyl monoglycidyl isocyanurate and1,3,5,7-tetramethylcyclotetrasiloxane, a reaction product of vinylnorbornene and bisdimethylsilylbenzene, and the like.

(Other Reactive Groups in Component (A))

The component (A) may contain other reactive groups. Examples of suchreactive groups include an epoxy group, amino group,radical-polymerizable unsaturated groups, carboxyl group, isocyanategroup, hydroxyl group, and alkoxysilyl groups. In the case where thecomponent (A) contains such a functional group, the resulting curableresin composition tends to have high adhesion property, and the strengthof a cured product to be obtained tends to be high. An epoxy group ispreferred among the functional groups in view of the possibility ofhigher adhesion. In view of higher thermal resistance of a cured productto be obtained, the component (A) preferably contains at least onereactive group per molecule on average.

(Mixing of Component (A))

The component (A) may be used alone, or two or more kinds thereof may beused in admixture.

(Component (B))

The component (B) is a compound containing at least two SiH groups permolecule.

The component (B) is not particularly limited as long as it contains atleast two SiH groups per molecule, and usable examples thereof includecompounds containing at least two SiH groups per molecule described inWO96/15194.

In view of availability, preferred among these are acyclic and/or cyclicorganopolysiloxanes containing at least two SiH groups per molecule. Inview of good compatibility with the component (A), further preferred arecyclic polyorganosiloxanes containing at least two SiH groups permolecule, represented by the following formula (VI):

wherein R¹ represents an organic group having 1 to 6 carbon atoms, and nrepresents a number of 3 to 10.

The substituent R¹ in the compound represented by the formula (VI) ispreferably composed of C, H, and O. The substituent R¹ is morepreferably a hydrocarbon group, and still more preferably a methylgroup.

In view of easy availability, the compound represented by the formula(VI) is preferably 1,3,5,7-tetramethylcyclotetrasiloxane.

The molecular weight of the component (B) is not particularly limited,and the component (B) having any molecular weight may be favorably used.In view of better fluidity and easy homogeneous mixing with powders suchas the component (E) and the component (F), the component (B) having alow molecular weight is preferably used. In this case, the minimummolecular weight is preferably 50, and the maximum molecular weight ispreferably 100,000, more preferably 1,000, and still more preferably700.

The component (B) is preferably liquid at a temperature of 23° C. foreasy homogeneous mixing with other components, especially powders suchas the component (E) and the component (F), or more specifically,because of no need to liquefy the component (B) by heating to themelting point or higher for homogeneous mixing. The viscosity at 23° C.of the component (B) is preferably at most 50 Pa·s, more preferably atmost 20 Pa·s, and still more preferably at most 5 Pa·s. The viscositycan be measured with an E-type viscometer.

The component (B) may be used alone, or two or more kinds thereof may beused in admixture.

(Preferred Structure of Component (B))

From the viewpoint of good compatibility with the component (A) and lowvolatility of the component (B) leading to less possibility of causing aproblem of outgassing from a curable resin composition to be obtained,the component (B) is preferably a compound obtainable by ahydrosilylation reaction between an organic compound (α) having at leastone carbon-carbon double bond reactive with a SiH group per molecule anda compound (β) containing at least two SiH groups per molecule.

(Component (α))

As the component (α), the same compound (α1) as the organic compoundhaving at least two carbon-carbon double bonds reactive with SiH groupsper molecule, which is the component (A) mentioned above, may be used.The use of the component (α1) tends to lead to high crosslink density ofa cured product to be obtained, and therefore high mechanical strengthof the cured product.

Furthermore, an organic compound (α2) having one carbon-carbon doublebond reactive with a SiH group per molecule may also be used. When thecomponent (α2) is used, a cured product to be obtained tends to have lowelasticity.

(Component (α2))

The component (α2) is not particularly limited as long as it is anorganic compound having one carbon-carbon double bond reactive with aSiH group per molecule. In view of good compatibility between thecomponent (B) and the component (A), the component (α2) is preferably acompound containing constituent elements selected exclusively from C, H,N, O, S, and halogens, but not a compound containing a siloxane unit(Si—O—Si) such as polysiloxane-organic block copolymers andpolysiloxane-organic graft copolymers.

The bonding site of the carbon-carbon double bond reactive with a SiHgroup in the component (α2) is not particularly limited, and may beanywhere in the molecule.

Compounds as the component (α2) are classified into polymeric compoundsand monomeric compounds.

Examples of the polymeric compounds include polysiloxane compounds,polyether compounds, polyester compounds, polyarylate compounds,polycarbonate compounds, saturated hydrocarbon compounds, unsaturatedhydrocarbon compounds, polyacrylic acid ester compounds, polyamidecompounds, phenol-formaldehyde compounds (phenol resin compounds), andpolyimide compounds.

Examples of the monomeric compounds include phenol compounds, bisphenolcompounds, aromatic hydrocarbon compounds such as benzene andnaphthalene; aliphatic hydrocarbon compounds such as linear or alicycliccompounds; heterocyclic compounds; silicon compounds; and mixturesthereof.

Although the carbon-carbon double bond reactive with a SiH group of thecomponent (α2) is not particularly limited, it is preferably a grouprepresented by the following formula (I):

wherein R¹ represents a hydrogen atom or a methyl group, in view ofreactivity. In view of easy availability of materials, a grouprepresented by the following formula:

is particularly preferred.

The carbon-carbon double bond reactive with a SiH group of the component(α2) is preferably an alicyclic group represented by the followingformula (II):

wherein R²s each represent a hydrogen atom or a methyl group, in view ofhigh thermal resistance of the cured product. In view of easyavailability of materials, an alicyclic group represented by thefollowing formula:

is particularly preferred.

The carbon-carbon double bond reactive with a SiH group may be directlybonded to a skeletal portion of the component (α2), or may be covalentlybonded thereto via a bivalent or higher valent substituent. The bivalentor higher valent substituent is not particularly limited as long as itis a substituent having a carbon number of 0 to 10. In view of bettercompatibility of the component (B) with the component (A), substituentscontaining constituent elements selected exclusively from C, H, N, O, Sand halogens are preferred. Examples of these substituents include thoserepresented by the following formulae.

Moreover, two or more of these bivalent or higher valent substituentsmay be covalently bonded to form one bivalent or higher valentsubstituent.

Examples of such a group to be covalently bonded to the skeletal portionmentioned above include a vinyl group, allyl group, methallyl group,acryl group, methacryl group, 2-hydroxy-3-(allyloxy)propyl group,2-allylphenyl group, 3-allylphenyl group, 4-allylphenyl group,2-(allyloxy)phenyl group, 3-(allyloxy)phenyl group, 4-(allyloxy)phenylgroup, 2-(allyloxy)ethyl group, 2,2-bis(allyloxymethyl)butyl group,3-allyloxy-2,2-bis(allyloxymethyl)propyl group, and groups representedby following formulae:

and the like.

Specific examples of the component (α2) include aliphatic acyclichydrocarbon compounds such as propene, 1-butene, 1-pentene, 1-hexene,1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-undecene,Linealene species (products of Idemitsu Petrochemical),4,4-dimethyl-1-pentene, 2-methyl-1-hexene, 2,3,3-trimethyl-1-butene and2,4,4-trimethyl-1-pentene; aliphatic cyclic hydrocarbon compounds suchas cyclohexene, methylcyclohexene, methylenecyclohexane, norbornylene,ethylidenecyclohexane, vinylcyclohexane, camphene, carene, α-pinene andβ-pinene; aromatic hydrocarbon compounds such as styrene,α-methylstyrene, indene, phenylacetylene, 4-ethynyltoluene, allylbenzeneand 4-phenyl-1-butene; allyl ethers such as alkyl allyl ethers and allylphenyl ether; aliphatic compounds such as glycerol monoallyl ether,ethylene glycol monoallyl ether and 4-vinyl-1,3-dioxolan-2-one; aromaticcompounds such as 1,2-dimethoxy-4-allylbenzene and o-allylphenol;substituted isocyanurates such as monoallyl dibenzyl isocyanurate andmonoallyl diglycidyl isocyanurate; and silicon compounds such asvinyltrimethylsilane, vinyltrimethoxysilane and vinyltriphenylsilane.Furthermore, specific examples of the component (α2) include polymers oroligomers containing a vinyl group at one terminal, including polyetherresins such as polyethylene oxide allylated at one terminal andpolypropylene oxide allylated at one terminal; hydrocarbon resins suchas polyisobutylene allylated at one terminal; and acrylic resins such aspolybutyl acrylate allylated at one terminal and polymethyl methacrylateallylated at one terminal.

The structure of the component (α2) may be linear or branched. Themolecular weight of the component (α2) is not particularly limited andthose having various molecular weights may be used. The molecular weightdistribution is not particularly limited, either. From the viewpointthat the viscosity of the mixture is reduced and the moldability is moreimproved, the molecular weight distribution is preferably not higherthan 3, more preferably not higher than 2, and still more preferably nothigher than 1.5.

In the case where the component (α2) has a glass transition temperature,the glass transition temperature is not particularly limited and thosehaving various glass transition temperatures may be used. From theviewpoint that a cured product to be obtained tends to be tough, theglass transition temperature is preferably not higher than 100° C., morepreferably not higher than 50° C., and still more preferably not higherthan 0° C. Preferred examples of the resin include polybutyl acrylateresins. Meanwhile, in view of higher thermal resistance of a curedproduct to be obtained, the glass transition temperature is preferablynot lower than 100° C., more preferably not lower than 120° C., stillmore preferably not lower than 150° C., and most preferably not lowerthan 170° C. A tan δ peak temperature obtained in a dynamicviscoelasticity measurement is determined as the glass transitiontemperature.

The component (α2) is preferably a hydrocarbon compound in view ofhigher thermal resistance of a cured product to be obtained. In thiscase, the lower limit of the number of carbons is preferably 7, and theupper limit of the number of carbons is preferably 10.

The component (α2) may contain other reactive groups. Examples of suchreactive groups include an epoxy group, amino group,radical-polymerizable unsaturated groups, carboxyl group, isocyanategroup, hydroxyl group, and alkoxysilyl groups. In the case where thecomponent (α2) contains such a functional group, the resulting curableresin composition tends to have high adhesion property, and the strengthof a cured product to be obtained tends to be high. An epoxy group ispreferred among the functional groups in view of the possibility ofhigher adhesion. In view of higher thermal resistance of a cured productto be obtained, the component (α2) preferably contains at least onereactive group per molecule on average. Specific examples of thecomponent (α2) include monoallyl diglycidyl isocyanurate, allyl glycidylether, allyloxyethylmethacrylate, allyloxyethyl acrylate, andvinyltrimethoxysilane.

As the component (α1) or/and the component (α2) mentioned above, asingle species may be used, or a plurality of species may be used incombination.

(Component (β))

The component (β) is a compound containing at least two SiH groups permolecule. Examples thereof include acyclic and/or cyclicpolyorganosiloxanes.

Specifically, for example, compounds represented by the followingformulae:

may be mentioned.

Particularly, in view of better compatibility with the component (α),preferred are cyclic polyorganosiloxanes containing at least three SiHgroups per molecule, represented by the following formula (VI):

wherein R¹ represents an organic group having 1 to 6 carbon atoms, and nrepresents a number of 3 to 10.

The substituent R¹ in the compound represented by the formula (VI) ispreferably composed of C, H and O. The substituent R¹ is more preferablya hydrocarbon group, and still more preferably a methyl group.

In view of easy availability, 1,3,5,7-tetramethylcyclotetrasiloxane ispreferred.

Other examples of the component (β) include compounds containing a SiHgroup, such as bisdimethylsilylbenzene.

The components (β) as mentioned above may be used alone, or two or morekinds thereof may be used in admixture.

(Reaction Between Component (α) and Component (β))

The following description will discuss a hydrosilylation reactionbetween the component (α) and the component (β) in the case a compoundobtainable by a hydrosilylation reaction between the component (α) andthe component (β) is used as the component (B) in the present invention.

Here, the hydrosilylation reaction between the component (α) and thecomponent (β) may give a mixture of a plurality of compounds includingthe component (B) in the present invention. In this case, the curableresin composition of the present invention can be prepared by using themixture as it is without separating the component (B).

In the case of subjecting the component (α) and the component (β) to ahydrosilylation reaction, the mixing ratio of the component (α) and thecomponent (β) is not particularly limited. Considering the strength of acured product obtained by a hydrosilylation reaction between thecomponent (B) to be obtained and the component (A), the number of SiHgroups in the component (B) is preferably larger. Therefore, generally,the total number (X) of carbon-carbon double bonds reactive with SiHgroups in the component (α) to be mixed and the total number (Y) of SiHgroups in the component (β) to be mixed preferably satisfy the ratio:Y/X≧2, and more preferably Y/X≧3. In view of better compatibility of thecomponent (B) with the component (A), the X and Y preferably satisfy theratio: 10≧Y/X, and more preferably 5≧Y/X.

An appropriate catalyst may be used in the hydrosilylation reaction ofthe component (α) and the component (β). The following may be used asthe catalyst: a simple substance of platinum; solid platinum supportedby a carrier such as alumina, silica, and carbon black; chloroplatinicacid; complexes of chloroplatinic acid with an alcohol, aldehyde,ketone, or the like; platinum-olefin complexes (e.g.,Pt(CH₂═CH₂)₂(PPh₃)₂, Pt(CH₂═CH₂)₂Cl₂), platinum-vinylsiloxane complexes(e.g., Pt(ViMe₂SiOSiMe₂Vi)_(n), Pt[(MeViSiO)₄]_(m)), platinum-phosphinecomplexes (e.g., Pt(PPh₃)₄, Pt(PBu₃)₄), platinum-phosphite complexes(e.g., Pt[P(OPh)₃]₄, Pt[P(OBu)₃]₄) (in those formulae, Me is a methylgroup, Bu is a butyl group, Vi is a vinyl group, Ph is a phenyl group,and n and m are integers); dicarbonyldichloroplatinum; Karstedtcatalysts; platinum-hydrocarbon complexes described in Ashby's U.S. Pat.Nos. 3,159,601 and 3,159,662; and platinum alcoholate catalystsdescribed in Lamoreaux's U.S. Pat. No. 3,220,972. In addition, platinumchloride-olefin complexes described in Modic's U.S. Pat. No. 3,516,946are also usable in the present invention.

Other examples of the catalyst except platinum compounds includeRhCl(PPh)₃, RhCl₃, RhAl₂O₃, RuCl₃, IrCl₃, FeCl₃, AlCl₃, PdCl₂.2H₂O,NiCl₂, and TiCl₄.

In view of catalytic activity, chloroplatinic acid, platinum-olefincomplexes, platinum-vinylsiloxane complexes, and the like are preferredamong the above examples. These catalysts may be used alone, or two ormore kinds thereof may be used in combination.

The amount of the catalyst added is not particularly limited. Forachieving sufficient curing and keeping the costs of the curable resincomposition relatively low, the minimum amount is preferably 10⁻⁸ mol,and more preferably 10⁻⁶ mol, per mol of SiH groups in the component(β). The maximum amount is preferably 10⁻¹ mol, and more preferably 10⁻²mol, per mol of SiH groups in the component (β).

A promoter may be used along with the catalyst. Examples of the promoterinclude phosphorus compounds such as triphenylphosphine; 1,2-diestercompounds such as dimethyl maleate; acetylene alcohol compounds such as2-hydroxy-2-methyl-1-butyne; sulfur compounds such as a simple substanceof sulfur; and amine compounds such as triethylamine. The amount of thepromoter added is not particularly limited, but the minimum amount ispreferably 10⁻² mol, and more preferably 10⁻¹ mol, and the maximumamount is preferably 10² mol, and more preferably 10 mol, per mol of thehydrosilylation catalyst.

Various methods may be employed for mixing the component (α), thecomponent (β), and the catalyst for reaction. Preferred is a method ofpreliminarily mixing the component (α) with the catalyst, and thenmixing the mixture with the component (β). A method of adding thecatalyst to a mixture of the component (α) and the component (β) leadsto difficulty in controlling the reaction. In the case of a method ofadding the component (α) to a mixture of the component (β) and thecatalyst, the component (β) may be altered because the component (β) canreact with existing moisture in the presence of the catalyst.

Various temperatures may be employed for the reaction. The lower limitof the temperature range is preferably 30° C., and more preferably 50°C., and the upper limit of the temperature range is preferably 200° C.,and more preferably 150° C. in the reaction. Low reaction temperaturesprolong the time for sufficient reaction, and high reaction temperaturesare not practical. The reaction may be performed at a constanttemperature, or may be performed while the temperature is changed inmultiple steps or continuously as needed.

Various reaction times and various pressures during the reaction may beemployed as needed.

A solvent may be used in the hydrosilylation reaction. The usablesolvent is not particularly limited as long as it does not inhibit thehydrosilylation reaction. Specifically, suitable examples of the solventinclude hydrocarbon solvents such as benzene, toluene, hexane, andheptane; ether solvents such as tetrahydrofuran, 1,4-dioxane,1,3-dioxolane, and diethyl ether; ketone solvents such as acetone, andmethyl ethyl ketone; and halogen solvents such as chloroform, methylenechloride, and 1,2-dichloroethane. A mixed solvent containing two or moresolvents may be used as the solvent. Toluene, tetrahydrofuran,1,3-dioxolane, and chloroform are preferred as the solvent. The amountof the solvent to be used may be appropriately set.

Various other additives may be used in order to, for example, controlthe reactivity.

After the reaction between the component (α) and the component (β), thesolvent or/and the unreacted component (α) or/and component (β) may beremoved. By removing these volatiles, the resulting component (B) doesnot contain any volatiles so that problems of voids and cracks caused byvolatilization of volatiles are less likely to occur during curing withthe component (A). Examples of the removal method include vacuumdistillation, and treatment with activated carbon, aluminum silicate,silica gel, or the like. The vacuum distillation is preferably performedat low temperatures. In this case, the upper limit of the temperature ispreferably 100° C., and more preferably 60° C. Treatment at hightemperatures tends to lead to alteration such as thickening.

Examples of the component (B) that is a reaction product of thecomponent (α) and the component (β) as mentioned above include areaction product of bisphenol A diallyl ether and1,3,5,7-tetramethylcyclotetrasiloxane, a reaction product ofvinylcyclohexene and 1,3,5,7-tetramethylcyclotetrasiloxane, a reactionproduct of divinylbenzene and 1,3,5,7-tetramethylcyclotetrasiloxane, areaction product of dicyclopentadiene and1,3,5,7-tetramethylcyclotetrasiloxane, a reaction product of triallylisocyanurate and 1,3,5,7-tetramethylcyclotetrasiloxane, a reactionproduct of diallyl monoglycidyl isocyanurate and1,3,5,7-tetramethylcyclotetrasiloxane, a reaction product of allylglycidyl ether and 1,3,5,7-tetramethylcyclotetrasiloxane, a reactionproduct of α-methylstyrene and 1,3,5,7-tetramethylcyclotetrasiloxane, areaction product of monoallyl diglycidyl isocyanurate and1,3,5,7-tetramethylcyclotetrasiloxane, a reaction product of vinylnorbornene and bisdimethylsilylbenzene, and the like.

(Mixing of Component (A) and Component (B))

Examples of combinations of the component (A) and the component (B)include various combinations of the compounds mentioned as examples ofthe component (A) or mixtures thereof, and the compounds mentioned asexamples of the component (B) or mixtures thereof.

The mixing ratio of the component (A) and the component (B) is notparticularly limited as long as the required strength is not lost. Withrespect to the ratio of the number (Y) of SiH groups in the component(B) to the number (X) of carbon-carbon double bonds in the component(A), the lower limit of the ratio is preferably Y/X≧0.3, more preferablyY/X≧0.5, and still more preferably Y/X≧0.7, and the upper limit of theratio is preferably 3≧Y/X, more preferably 2≧Y/X, and still morepreferably 1.5≧Y/X. If the ratio is not in these preferred ranges, asufficient strength may not be achieved, or thermal deterioration maytend to occur easily.

(Component (C))

The component (C) is a hydrosilylation catalyst.

The hydrosilylation catalyst is not particularly limited as long as itcatalyzes a hydrosilylation reaction. Examples of the catalyst include asimple substance of platinum; solid platinum supported by a carrier suchas alumina, silica, carbon black or the like; chloroplatinic acid;complexes of chloroplatinic acid with an alcohol, aldehyde, ketone, orthe like; platinum-olefin complexes (e.g., Pt(CH₂═CH₂)₂(PPh₃)₂,Pt(CH₂═CH₂)₂Cl₂), platinum-vinylsiloxane complexes (e.g.,Pt(ViMe₂SiOSiMe₂Vi)_(n), Pt[(MeViSiO)₄]_(m)), platinum-phosphinecomplexes (e.g. , Pt(PPh₃)₄, Pt(PBu₃)₄), platinum-phosphite complexes(e.g., Pt[P(OPh)₃]₄, Pt[P(OBu)₃]₄) (in those formulae, Me is a methylgroup, Bu is a butyl group, Vi is a vinyl group, Ph is a phenyl group,and n and m are integers); dicarbonyldichloroplatinum; Karstedtcatalysts; platinum-hydrocarbon complexes described in Ashby's U.S. Pat.Nos. 3,159,601 and 3,159,662; and platinum alcoholate catalystsdescribed in Lamoreaux's U.S. Pat. No. 3,220,972. In addition, platinumchloride-olefin complexes described in Modic's U.S. Pat. No. 3,516,946are also usable in the present invention.

Other examples of the catalyst except platinum compounds includeRhCl(PPh)₃, RhCl₃, RhAl₂O₃, RuCl₃, IrCl₃, FeCl₃, AlCl₃, PdCl₂.2H₂O,NiCl₂, and TiCl₄.

In view of catalytic activity, chloroplatinic acid, platinum-olefincomplexes, platinum-vinylsiloxane complexes, and the like are preferredamong the above examples. These catalysts may be used alone, or two ormore kinds thereof may be used in combination.

The amount of the catalyst added is not particularly limited. Forachieving sufficient curing and keeping the costs of the curable resincomposition relatively low, the minimum amount is preferably 10⁻⁸ mol,and more preferably 10⁻⁶ mol, per mol of SiH groups in the component(B). The maximum amount is preferably 10⁻¹ mol, and more preferably 10⁻²mol, per mol of SiH groups in the component (B).

A promoter may be used along with the catalyst. Examples of the promoterinclude phosphorus compounds such as triphenylphosphine; 1,2-diestercompounds such as dimethyl maleate; acetylene alcohol compounds such as2-hydroxy-2-methyl-1-butyne; sulfur compounds such as a simple substanceof sulfur; and amine compounds such as triethylamine. The amount of thepromoter added is not particularly limited. The minimum amount ispreferably 10⁻² mol, and more preferably 10⁻¹ mol, and the maximumamount is preferably 10² mol, and more preferably 10 mol, per mol of thehydrosilylation catalyst.

(Component (D))

The component (D) in the present invention is a silicone compound havingat least one carbon-carbon double bond reactive with a SiH group permolecule. The component (D), when mixed with an inorganic filler as thecomponent (E), enables the curable resin composition to give a curedproduct having a lower linear expansion coefficient.

The silicone compound as the component (D) is a compound having askeleton substantially formed of Si—O—Si bonds. Various kinds ofcompounds including those having a linear, circular, or branchedstructure or having a partial network may be used.

Examples of substituents that may be bonded to such a skeleton includealkyl groups such as a methyl group, ethyl group, propyl group, andoctyl group; aryl groups such as a phenyl group, 2-phenylethyl group,and 2-phenylpropyl group; alkoxy groups such as a methoxy group, ethoxygroup, and isopropoxy group; and a hydroxyl group. In view of highertendency of higher thermal resistance, a methyl group, phenyl group,hydroxyl group, and methoxy group are preferred, and a methyl group andphenyl group are more preferred among the above examples. Examples ofthe substituents containing a carbon-carbon double bond reactive with aSiH group include a vinyl group, allyl group, acryloxy group,methacryloxy group, acryloxypropyl group, and methacryloxypropyl group.In view of good reactivity, a vinyl group is preferred among theexamples.

Examples of the component (D) may include compounds representable by thefollowing formula:R_(n)(CH₂═CH)_(m)SiO_((4-n-m)/2)wherein R represents a group selected from a hydroxyl group, a methylgroup, and a phenyl group, and n and m each represent a numbersatisfying 0≦n<4, 0<m≦4, and 0<n+m≦4).

Examples of the component (D) include polydimethylsiloxane,polydiphenylsiloxane and polymethylphenylsiloxane each containing avinyl group as a terminal group or side-chain group, and random or blockcopolymers of two or three kinds thereof,1,3-divinyltetramethyldisiloxane, and1,3,5,7-tetravinylcyclotetrasiloxane. A plurality of the components (D)may be used in admixture.

Among the above examples, because the effects of the present inventionbecome larger, linear polysiloxanes containing a vinyl group at aterminal thereof are preferred, linear polysiloxanes containing a vinylgroup at both terminals thereof are more preferred, linearpolymethylphenylsiloxanes containing a vinyl group at both terminalsthereof are still more preferred, and linear polymethylphenylsiloxanescontaining a vinyl group at both terminals thereof and having a phenylcontent of not less than 20 mol % of the total substituents areparticularly preferred.

Regarding the molecular weight of the component (D), the weight averagemolecular weight (Mw) of the component (D) is preferably not less than1,000, more preferably not less than 5,000, and still more preferablynot less than 10,000. A larger molecular weight tends to lead to furtherreduction in stress of a cured product to be obtained. The molecularweight of the component (D) is preferably not more than 1,000,000, andmore preferably not more than 100,000. A larger molecular weight leadsto less compatibility with the component (A).

Regarding the amount of the component (D), the weight of the component(D) is preferably not less than 30% by weight, more preferably not lessthan 50% by weight, and still more preferably not less than 80% byweight, of the total weight of the component (A) and the component (B).

The mixing ratio of the component (A), the component (B), and thecomponent (D) is not particularly limited as long as the requiredstrength is not lost. With respect to the ratio of the number (Y) of SiHgroups in the component (B) to the number (X) of carbon-carbon doublebonds reactive with SiH groups in the component (A) and the component(D), the lower limit of the ratio is preferably Y/X≧0.3, more preferablyY/X≧0.5, and still more preferably Y/X≧0.7, and the upper limit of theratio is preferably 3≧Y/X, more preferably 2≧Y/X, and still morepreferably 1.5≧Y/X. If the ratio is not in these preferred ranges, asufficient strength may not be achieved, or thermal deterioration tendsto occur easily.

The component (E) is an inorganic filler.

The component (E) has an effect in enhancing the strength and hardnessof a cured product to be obtained, and in reducing its linear expansioncoefficient.

Various substances can be used as the inorganic filler (E). Examplesthereof include silica-based inorganic fillers such as quartz, fumedsilica, precipitated silica, silicic anhydride, fused silica,crystalline silica and ultrafine amorphous silica; inorganic fillerssuch as alumina, zircon, titanium oxide, zinc oxide, silicon nitride,boron nitride, aluminum nitride, silicon carbide, glass fiber, aluminafiber, carbon fiber, mica, graphite, carbon black, graphite,diatomaceous earth, white clay, clay, talc, aluminum hydroxide, calciumcarbonate, magnesium carbonate, barium sulfate, barium titanate,potassium titanate, calcium silicate, inorganic balloons, and silverpowder; and other inorganic fillers commonly used or/and proposed asfillers for conventional sealing materials such as epoxy sealingmaterials. In view of less damage to semiconductor elements, theinorganic filler is preferably less radioactive.

The inorganic filler may be appropriately surface-treated. Examples ofthe surface treatment include alkylation treatment, trimethylsilylationtreatment, silicone treatment, and treatment with a coupling agent.

Examples of the coupling agent for such treatment include silanecoupling agents. The silane coupling agents are not limited inparticular as long as they are compounds each containing at least oneeach of a functional group reactive with an organic group, and ahydrolysable silicon group per molecule. As the functional groupreactive with an organic group, at least one functional group selectedfrom the group consisting of an epoxy group, methacryl group, acrylgroup, isocyanate group, isocyanurate group, vinyl group and carbamategroup is preferred in view of handleability, and an epoxy group,methacryl group and acryl group are particularly preferred in view ofcurability and adhesion. As the hydrolysable silicon group, alkoxysilylgroups are preferred in view of handleability, and a methoxysilyl groupand ethoxysilyl group are particularly preferred in view of reactivity.

Preferred examples of the silane coupling agent include alkoxysilanescontaining an epoxy functional group, such as3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and2-(3,4-epoxycyclohexyl)ethyltriethoxysilane; and alkoxysilanescontaining a methacryl group or an acryl group, such as3-methacryloxypropyltrimethoxysilane,3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane,3-acryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane,methacryloxymethyltriethoxysilane, acryloxymethyltrimethoxysilane andacryloxymethyltriethoxysilane.

Other methods may be mentioned as the method for adding the inorganicfiller. For example, a method may be mentioned in which a hydrolysablesilane monomer or oligomer such as alkoxysilanes, acyloxysilanes andhalogenated silanes, or an alkoxide, acyloxide or halide of a metal suchas titanium or aluminum, or the like is added to the curable resincomposition of the present invention and allowed to react in the curableresin composition or a partial reaction product of the curable resincomposition to generate an inorganic filler in the curable resincomposition.

Silica-based inorganic fillers are preferred among the above inorganicfillers from the viewpoint of less possibility of inhibiting the curingreaction, larger effect of reducing the linear expansion coefficient,and higher adhesion to a lead frame. Moreover, in view of good balanceof physical properties such as moldability and electric properties,fused silica is preferred. From the viewpoint that the thermalconductivity of the package tends to be high, which enables packagedesigns with high heat dissipation performance, crystalline silica ispreferred. For higher heat dissipation performance, alumina ispreferred. In view of high light reflectance of the package resin, whichleads to higher light extraction efficiency of a light-emitting diode tobe obtained, titanium oxide is preferred. In addition, in view of highreinforcing effect which leads to higher strength of the package, glassfiber, potassium titanate, and calcium silicate are preferred.

The average particle size and particle size distribution of theinorganic filler are not particularly limited, and those having variousvalues may be used such as inorganic fillers used or/and proposed asfillers for conventional sealing materials such as epoxy sealingmaterials. The minimum average particle size is usually 0.1 μm, and ispreferably 0.5 μm in view of better fluidity. The maximum averageparticle size is usually 120 μm, and is preferably 60 μm, and morepreferably 15 μm in view of better fluidity.

Inorganic fillers having various specific surface areas may also be usedsuch as those used or/and proposed as fillers for conventional sealingmaterials such as epoxy sealing materials.

The inorganic fillers may have various shapes such as a crushed shape, aflake shape, a spherical shape, and a bar shape. Inorganic fillershaving various aspect ratios may also be used. The aspect ratio ispreferably not less than 10 in view of higher strength of a curedproduct to be obtained. Moreover, considering isotropic shrinkage of theresin, the inorganic filler preferably has a powder form rather than afiber form. Alternatively, a spherical shape is preferred in view ofbetter fluidity during molding even if the inorganic filler is highlyfilled.

These inorganic fillers may be used alone, or two or more kinds thereofmay be used in combination.

Although the amount of the component (E) is not particularly limited,the total amount of the component (E) is preferably 70% by weight ormore, more preferably 80% by weight of more, and still more preferably90% by weight or more, of the whole curable resin composition. A smallamount of the component (E) is less likely to have an effect inenhancing the strength and hardness and in reducing the linear expansioncoefficient.

Regarding the order of mixing the inorganic filler as the component (E),various methods are applicable. However, in view of better storagestability of intermediate materials for the curable resin composition, amethod is preferred in which the component (A) is mixed with thecomponent (C) and the inorganic filler, and then the resulting mixtureis mixed with the component (B). In the case of a method of mixing thecomponent (B) with the component (C) and/or the inorganic filler, andthen mixing the resulting mixture with the component (A), since thecomponent (B) can react with moisture in the environment and/or theinorganic filler in the presence or absence of the component (C), thecomponent (B) may be altered during storage or the like. Moreover, fromthe viewpoint that the reactive components (A), (B), and (C) tend to bewell mixed to give a stable molded product, it is preferable to mix theinorganic filler with a mixture of the component (A), the component (B),and the component (C).

As the means of mixing the inorganic filler as the component (E),various means conventionally employed and/or proposed for epoxy resin orthe like may be employed. Examples of the means include mixers such astwo-roll or three-roll mills, planetary mixing and defoaming machines,homogenizers, dissolvers, and planetary mixers, and melt mixers such asPlastomill. Among these, three-roll mills and melt mixers are preferredfrom the viewpoint that sufficient dispersibility of the inorganicfiller tends to be achieved even if the filler is highly filled. Theinorganic filler may be mixed at normal temperature or under heating,and also may be mixed at ordinary pressure or in vacuum. From theviewpoint that sufficient dispersibility of the inorganic filler tendsto be achieved even if the inorganic filler is highly filled, the mixingis preferably performed under heating. From the viewpoint that thewettability of the surface of the inorganic filler tends to be enhanced,and sufficient dispersibility tends to be achieved, the mixing ispreferably performed in vacuum.

(Component (F))

The curable resin composition of the present invention may preferablycontain a white pigment (component (F)).

The component (F) is a white pigment, and has an effect in enhancing thelight reflectance of a cured product to be obtained.

Various substances may be used as the component (F), and examplesthereof include titanium oxide, zinc oxide, magnesium oxide, antimonyoxide, zirconium oxide, strontium oxide, niobium oxide, boron nitride,barium titanate, zinc sulfide, barium sulfate, magnesium carbonate, andhollow glass particles. From the viewpoint of easy handleability,availability and cost, titanium oxide or zinc oxide is preferred amongthese examples.

Various titanium oxides may be used as the component (F), and may beanatase types or rutile types. In view of no photocatalytic activity andof higher stability of the curable resin composition, rutile types arepreferred.

As the component (F), those having various average particle sizes may beused. However, in view of higher light reflectance of a cured product tobe obtained and greater hardness of the curable resin compositiontablet, the component (F) preferably has an average particle size of notmore than 1.0 μm, more preferably not more than 0.30 μm, and mostpreferably not more than 0.25 μm.

Meanwhile, from the viewpoint of high fluidity of the curable resincomposition, the average particle size is preferably not less than 0.05μm, and more preferably not less than 0.1 μm.

The average particle size can be measured using a laserdiffraction/scattering particle size distribution analyzer.

Titanium oxides produced by any methods including the sulfate processand the chloride process, may be used as the titanium oxide as thecomponent (F).

The component (F) may be surface-treated.

In the surface treatment of the component (F), the surface of thecomponent (F) is coated with at least one selected from inorganiccompounds and organic compounds. Examples of the inorganic compoundsinclude aluminum compounds, silicon compounds, zirconium compounds, tincompounds, titanium compounds and antimony compounds. Examples of theorganic compounds include polyhydric alcohols, alkanolamines orderivatives thereof, organosilicon compounds such as organosiloxanes,higher fatty acids or metal salts thereof, and organometallic compounds.

In the case where the surface of the component (F) is coated with aninorganic compound or organic compound, the surface treatment may beperformed by a known method such as a wet method or a dry method whentitanium oxide is, for example, dry-ground, made into a slurry, orwet-ground. Various other methods may also be mentioned such as a liquidphase method and a gas phase method.

Treatment with an organosiloxane, among the above examples, is preferredbecause this treatment contributes to high light reflectance of a curedproduct to be obtained, and good thermal and light resistance. Moreover,inclusion of titanium oxide surface-treated with an organosiloxane isfavorable for producing an excellent light-emitting diode which has highlight-extraction efficiency and maintains the light-extractionefficiency even after a long time use.

Various organosiloxane agents are applicable for such surface treatment.Examples thereof include silane coupling agents exemplified by, forexample, polysiloxanes such as polydimethylsiloxane,polymethylphenylsiloxane, polymethylhydrogensiloxanes, and copolymersthereof; cyclosiloxanes such as hexamethylcyclotrisiloxane,heptamethylcyclotetrasiloxane, and1,3,5,7-tetramethylcyclotetrasiloxane; various silanes includingchlorosilanes such as trimethylchlorosilane, dimethyldichlorosilane andmethyltrichlorosilane; silanes containing an epoxy functional group suchas 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and2-(3,4-epoxycyclohexyl)ethyltriethoxysilane; silanes containing amethacryl group or an acryl group such as3-methacryloxypropyltrimethoxysilane,3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane,3-acryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane,methacryloxymethyltriethoxysilane, acryloxymethyltrimethoxysilane andacryloxymethyltriethoxysilane; silanes containing a vinyl group such asvinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane,vinyltris(β-methoxyethoxy)silane and vinyltriacetoxysilane;mercaptosilanes such as γ-mercaptopropyltrimethoxysilane andγ-mercaptopropylmethyldimethoxysilane; silanes containing an amino groupsuch as γ-aminopropyltriethoxysilane,γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane,N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,γ-(β-aminoethyl)aminopropyldimethoxymethylsilane,N-(trimethoxysilylpropyl)ethylenediamine,N-(dimethoxymethylsilylisopropyl)ethylenediamine andN-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane; silanescontaining an isocyanate group such as isocyanatepropyltrimethoxysilaneand isocyanatepropyltriethoxysilane; silanes containing an alkyl groupsuch as methyltrimethoxysilane, methyltriethoxysilane,hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane andoctyltriethoxysilane; and other silanes such asγ-chloropropyltrimethoxysilane and γ-anilinopropyltrimethoxysilane, aswell as hexamethyldisiloxane, hexamethyldisilazane, and the like. Amongthese surface treatment agents, those not containing a carbon-carbondouble bond are preferred. Those containing a carbon-carbon double bondtend to reduce the thermal resistance. Moreover, surface treatment witha substance other than organosiloxanes, such as Al, Zr, Zn, or the like,may be concomitantly performed.

Furthermore, the component (F) may be surface-treated with an inorganiccompound.

The surface treatment with an inorganic compound is not particularlylimited, and examples thereof include various surface treatments withaluminum compounds, silicon compounds, zirconium compounds or the like.Titanium oxide is in some cases surface-treated with an inorganiccompound or organic compound for the purpose of enhancing thedurability, increasing the affinity for solvents, preventing loss ofshape in particles, or the like. It is considered that surface treatmentof the component (F) with an inorganic compound leads to higher affinityfor the components contained in the curable resin composition, andtherefore better dispersibility of the component (F) in the curableresin composition, thereby enhancing the strength of a cured product tobe obtained.

Various methods are applicable for the surface treatment, and examplesthereof include various methods such as a wet method, a dry method, aliquid phase method, and a gas phase method.

The amount of the component (F) is not particularly limited, and ispreferably not less than 10% by weight, more preferably not less than15% by weight, and still more preferably not less than 20% by weight, ofthe whole curable resin composition. If the amount is less than 10% byweight, the resulting cured product may have a reduced lightreflectance.

(Component (E) and Component (F))

The total amount of the component (E) and the component (F) is notparticularly limited; however, the total amount of the component (E) andthe component (F) is preferably not less than 85% by weight, and morepreferably not less than 90% by weight, of the whole curable resincomposition.

A small total amount of the component (E) and the component (F) is lesslikely to have an effect in enhancing the strength and hardness, and inreducing the linear expansion coefficient.

Regarding the order of mixing the component (F), various methods may beemployed. Preferred embodiments are similar to those described for thecomponent (E). Moreover, the component (F) and the component (E) may beadded simultaneously.

The means for mixing the component (F) may be the same as those formixing the component (E).

(Component (G))

The curable resin composition of the present invention may preferablycontain a metal soap (component (G)).

The component (G) is added for improving the moldability such as moldreleasability of the curable resin composition.

Various conventionally-used metal soaps may be used as the component(G). The metal soap herein generally refers to a product in which a longchain fatty acid is bonded to a metal ion, and any metal soap can beused as long as it has a nonpolar or low-polar moiety derived from thefatty acid and a polar moiety derived from the bonding site with themetal in a molecule. Examples of the long chain fatty acid includeC1-C18 saturated fatty acids, C3-C18 unsaturated fatty acids, andaliphatic dicarboxylic acids. Among these, C1-C18 saturated fatty acidsare preferred in view of easy availability and high industrialpracticability. Moreover, in view of effective mold releasability,C6-C18 saturated fatty acids are more preferred. Examples of the metalion include alkali metal ions, and alkaline earth metal ions, as well aszinc, cobalt, aluminum, and strontium ions. Specific examples of themetal soap include lithium stearate, lithium 12-hydroxystearate, lithiumlaurate, lithium oleate, lithium 2-ethylhexanoate, sodium stearate,sodium 12-hydroxystearate, sodium laurate, sodium oleate, sodium2-ethylhexanoate, potassium stearate, potassium 12-hydroxystearate,potassium laurate, potassium oleate, potassium 2-ethylhexanoate,magnesium stearate, magnesium 12-hydroxystearate, magnesium laurate,magnesium oleate, magnesium 2-ethylhexanoate, calcium stearate, calcium12-hydroxystearate, calcium laurate, calcium oleate, calcium2-ethylhexanoate, barium stearate, barium 12-hydroxystearate, bariumlaurate, zinc stearate, zinc 12-hydroxystearate, zinc laurate, zincoleate, zinc 2-ethylhexanoate, lead stearate, lead 12-hydroxystearate,cobalt stearate, aluminum stearate, manganese oleate, and bariumricinoleate. Among these metal soaps, metal stearates are preferred inview of easy availability and high safety which lead to high industrialpracticability. Particularly from the economic viewpoint, at least oneselected from the group consisting of calcium stearate, magnesiumstearate, and zinc stearate is most preferred.

The amount of the metal soap added is not particularly limited. Theminimum amount is preferably 0.01 parts by weight, more preferably 0.025parts by weight, and still more preferably 0.05 parts by weight,relative to 100 parts by weight of the whole curable resin composition.The maximum amount is preferably 5 parts by weight, and more preferably4 parts by weight, relative to 100 parts by weight of the whole curableresin composition. Addition of an excessive amount of the metal soap maylead to reduction in physical properties of the cured product. Additionof too small amount of the metal soap may not ensure mold releasability.

(Additives)

The curable resin composition of the present invention may containvarious additives.

(Curing Retardant)

In order to improve the storage stability of the curable resincomposition of the present invention, or to control the reactivity ofthe hydrosilylation reaction in the production process, a curingretardant may be used. Examples of the curing retardant includecompounds containing an aliphatic unsaturated bond, organophosphoruscompounds, organosulfur compounds, nitrogen-containing compounds, tincompounds and organic peroxides. These may be used in combination.

Examples of the compounds containing an aliphatic unsaturated bondinclude: propargyl alcohols such as 3-hydroxy-3-methyl-1-butyne,3-hydroxy-3-phenyl-1-butyne and 1-ethynyl-1-cyclohexanol; ene-ynecompounds; and maleates such as dimethyl maleate. Examples of theorganophosphorus compounds include triorganophosphines,diorganophosphines, organophosphones and triorganophosphites. Examplesof the organosulfur compounds include organomercaptans,diorganosulfides, hydrogen sulfide, benzothiazole, thiazole andbenzothiazole disulfide. Examples of the nitrogen-containing compoundsinclude ammonia, primary, secondary or tertiary alkylamines, arylamines,urea and hydrazine. Examples of the tin compounds include stannoushalide dihydrate and stannous carboxylates. Examples of the organicperoxides include di-tert-butyl peroxide, dicumyl peroxide, benzoylperoxide and tert-butyl peroxybenzoate.

In view of favorable retardation activity and good availability ofmaterials, preferred among these curing retardants are benzothiazole,thiazole, dimethyl maleate, 3-hydroxy-3-methyl-1-butyne and1-ethynyl-1-cyclohexanol.

Various amounts of the curing retardant may be added. The minimum amountof the curing retardant added is preferably 10⁻¹ mol, and morepreferably 1 mol, and the maximum amount is preferably 10³ mol, and morepreferably 50 mol, per mol of the hydrosilylation catalyst used.

These curing retardants may be used alone, or two or more of them may beused in combination.

(Adhesion Promoter)

An adhesion promoter may be added in the curable resin composition ofthe present invention. Examples of the adhesion promoter includecommonly used adhesives, as well as, for example, various couplingagents, epoxy compounds, phenol resins, coumarone-indene resins, rosinester resins, terpene-phenol resins, α-methylstyrene-vinyltoluenecopolymers, polyethylmethylstyrene and aromatic polyisocyanates.

Examples of the coupling agents include silane coupling agents andtitanate coupling agents.

Examples and preferred examples of the coupling agents are the same asthose mentioned above.

Although various amounts of the coupling agent may be added, the minimumamount is preferably 0.1 parts by weight, and more preferably 0.5 partsby weight, and the maximum amount is preferably 50 parts by weight, andmore preferably 25 parts by weight, relative to 100 parts by weight ofthe total of the component (A) and the component (B). If the amountadded is smaller, the adhesion-promoting effect may not be manifested,while if the amount added is larger, adverse effects may occur to thephysical properties of the cured product.

Examples of the epoxy compounds include novolac phenol epoxy resin,biphenyl epoxy resin, dicyclopentadiene epoxy resin, bisphenol Fdiglycidyl ether, bisphenol A diglycidyl ether,2,2′-bis(4-glycidyloxycyclohexyl)propane,3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate,vinylcyclohexene dioxide,2-(3,4-epoxycyclohexyl)-5,5-spiro-(3,4-epoxycyclohexane)-1,3-dioxane,bis(3,4-epoxycyclohexyl)adipate, 1,2-cyclopropanedicarboxylic acidbisglycidyl ester, and triglycidyl isocyanurate, monoallyl diglycidylisocyanurate, and diallyl monoglycidyl isocyanurate.

Various amounts of the epoxy compound may be added. The minimum amountis preferably 1 part by weight, and more preferably 3 parts by weight,and the maximum amount is preferably 50 parts by weight, and morepreferably 25 parts by weight, relative to 100 parts by weight of thetotal of the component (A) and the component (B). A smaller amount ofthe epoxy compound may fail to exert the adhesion-promoting effect, anda larger amount thereof may have adverse effects on the physicalproperties of the cured product.

Each of these coupling agents, silane coupling agents, epoxy compounds,and the like may be used alone, or two or more of these may be used incombination.

In the present invention, a silanol condensation catalyst may also beused for the purpose of enhancing the effects of the coupling agent orepoxy compound, and its use contributes to enhancement of adhesionand/or stabilization. Although the silanol condensation catalyst is notparticularly limited, it is preferably a boron compound or/and aluminumcompound or/and titanium compound. Examples of aluminum compounds usableas the silanol condensation catalyst include: aluminum alkoxides such asaluminum triisopropoxide, sec-butoxyaluminum diisopropoxide, andaluminum tri-sec-butoxide; and aluminum chelates such asethylacetoacetate aluminum diisopropoxide, aluminumtris(ethylacetoacetate), aluminum chelate M (produced by Kawaken FineChemicals Co., Ltd., alkylacetoacetate aluminum diisopropoxide),aluminum tris(acetylacetonate), and aluminum monoacetylacetonatebis(ethylacetoacetate). In view of handleability, aluminum chelates aremore preferred. Examples of titanium compounds usable as the silanolcondensation catalyst include: tetraalkoxy titaniums such astetraisopropoxy titanium and tetrabutoxy titanium; titanium chelatessuch as titanium tetraacetylacetonate; and general titanate couplingagents containing a residue such as oxyacetate or ethylene glycol.

Examples of boron compounds usable as the silanol condensation catalystinclude borate esters. Suitable examples of the borate esters includecompounds represented by the following formulae (VII) and V (III):B(OR¹)₃  (VII)B(OCOR¹)₃  (VIII)wherein R¹s each represent an organic group having 1 to 48 carbon atoms.

Preferred specific examples of the borate esters includetri-2-ethylhexyl borate, tri-n-octadecyl borate, tri-n-octyl borate,triphenyl borate, trimethylene borate, tris(trimethylsilyl)borate,tri-n-butyl borate, tri-sec-butyl borate, tri-tert-butyl borate,triisopropyl borate, tri-n-propyl borate, triallyl borate, triethylborate, trimethyl borate, and boron methoxyethoxide.

These borate esters may be used alone, or two or more of them may beused in admixture. Mixing may be performed in advance, or may beperformed upon producing cured products.

In view of easy availability and high industrial practicability,trimethyl borate, triethyl borate, and tri-n-butyl borate are preferred,and in particular, trimethyl borate is more preferred among the aboveborate esters.

In view of suppression of volatilization during curing, tri-n-octadecylborate, tri-n-octyl borate, triphenyl borate, trimethylene borate,tris(trimethylsilyl)borate, tri-n-butyl borate, tri-sec-butyl borate,tri-tert-butyl borate, triisopropyl borate, tri-n-propyl borate,triallyl borate, and boron methoxyethoxide are preferred, and inparticular, tri-n-octadecyl borate, tri-tert-butyl borate, triphenylborate, and tri-n-butyl borate are more preferred.

In terms of suppressed volatilization and good workability, tri-n-butylborate, triisopropyl borate, and tri-n-propyl borate are preferred, andespecially tri-n-butyl borate is more preferred.

In terms of less coloring under high temperatures, trimethyl borate andtriethyl borate are preferred, and especially trimethyl borate is morepreferred.

In the case where the silanol condensation catalyst is used, althoughvarious amounts may be used, the minimum amount of the silanolcondensation catalyst is preferably 0.1 parts by weight, and morepreferably 1 part by weight, while the maximum amount is preferably 50parts by weight, and more preferably 30 parts by weight, relative to 100parts by weight of the coupling agent or/and epoxy compound. If theaddition amount is smaller, then no adhesion-promoting effect may beachieved. If the addition amount is larger, adverse effects may occur tothe physical properties of the cured product.

These silanol condensation catalysts may be used alone, or two or morekinds thereof may be used in combination.

In order to further enhance the adhesion-promoting effect in the presentinvention, a silanol source compound may also be used, and its usecontributes to enhancement of adhesion and/or stabilization. Examples ofsuch a silanol source include: silanol compounds such as triphenylsilanol and diphenyldihydroxysilane; and alkoxysilanes such asdiphenyldimethoxysilane, tetramethoxysilane, and methyltrimethoxysilane.

In the case where the silanol source compound is used, although variousamounts may be used, the minimum amount of the silanol source compoundis preferably 0.1 parts by weight, and more preferably 1 part by weight,while the maximum amount is preferably 50 parts by weight, and morepreferably 30 parts by weight, relative to 100 parts by weight of thecoupling agent or/and epoxy compound. If the addition amount is smaller,no adhesion-promoting effect may be achieved. If the addition amount islarger, adverse effects may occur to the physical properties of thecured product.

These silanol source compounds may be used alone, or two or more kindsthereof may be used in combination.

In the present invention, in order to enhance the effects of thecoupling agent or epoxy compound, a carboxylic acid or/and an acidanhydride may be used, and its use contributes to enhancement ofadhesion and/or stabilization. Although such carboxylic acids and acidanhydrides are not particularly limited, examples thereof include thoserepresented by the following formulae:

and 2-ethylhexanoic acid, cyclohexanecarboxylic acid,cyclohexanedicarboxylic acid, methylcyclohexanedicarboxylic acid,tetrahydrophthalic acid, methyltetrahydrophthalic acid, methylhymicacid, norbornenedicarboxylic acid, hydrogenated methylnadic acid, maleicacid, acetylenedicarboxylic acid, lactic acid, malic acid, citric acid,tartaric acid, benzoic acid, hydroxybenzoic acid, cinnamic acid,phthalic acid, trimellitic acid, pyromellitic acid,naphthalenecarboxylic acid, naphthalenedicarboxylic acid, and anhydridesof one or more of these acids.

Among these carboxylic acids and/or acid anhydrides, ones containing acarbon-carbon double bond reactive with a SiH group are preferredbecause they have hydrosilylation reactivity and are less likely tobleed from a cured product to be obtained, so that the physicalproperties of the cured product are less likely to be impaired.Preferred examples of the carboxylic acids or/and acid anhydridesinclude those represented by the following formula:

and tetrahydrophthalic acid, methyltetrahydrophthalic acid, andanhydrides of one or more of these acids.

In the case where the carboxylic acid or/and acid anhydride is used,although various amounts thereof may be used, the minimum additionamount is preferably 0.1 parts by weight, and more preferably 1 part byweight, while the maximum addition amount is preferably 50 parts byweight, and more preferably 10 parts by weight, relative to 100 parts byweight of the coupling agent or/and epoxy compound. If the additionamount is smaller, then no adhesion-promoting effect may be achieved. Ifthe addition amount is larger, then adverse effects may occur to thephysical properties of the cured product.

These carboxylic acids or/and acid anhydrides may be used alone, or twoor more types thereof may be used in combination.

The curable resin composition of the present invention may containsilane compounds mentioned above. The silane compounds contribute toenhancement of adhesion to a lead, and are thus effective for preventinginvasion of water through an interface between the package and the lead.Examples of the silane compounds include dimethyldimethoxysilane,dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane,methylphenyldimethoxysilane, and methylphenyldiethoxysilane.Particularly, dimethyldimethoxysilane is preferred among these.

(Cured Product of Thermosetting Resin)

A cured product of a thermosetting resin may be crushed into particlesand then mixed. In the case where the thermosetting resin is used asdispersed particles, although various average particle sizes may beemployed, the minimum average particle size is preferably 10 nm, and themaximum average particle size is preferably 10 μm. The particle systemmay have a distribution, and may either be monodispersed or have aplurality of peak particle sizes. From the viewpoint that the viscosityof the curable resin composition tends to be low, and thus themoldability tends to be better, the coefficient of variation of theparticle size is preferably 10% or less.

(Thermoplastic Resin)

Various thermoplastic resins may be added in the curable resincomposition of the present invention for the purpose of, for example,improving the properties of the composition. Various thermoplasticresins are usable, and examples thereof include, but not limited to,acrylic resins typically exemplified by polymethyl methacrylate resins(for example, Optorez manufactured by Hitachi Chemical) such ashomopolymers of methyl methacrylate, and random, block or graftcopolymers of methyl methacrylate and other monomers, and polybutylacrylate resins such as homopolymers of butyl acrylate, and random,block or graft copolymers of butyl acrylate and other monomers;polycarbonate resins (for example, APEC manufactured by Teijin) such aspolycarbonate resins containing a monomer unit such as bisphenol A or3,3,5-trimethylcyclohexylidene bisphenol; cycloolefin resins (forexample, APEL manufactured by Mitsui Chemicals, ZEONOR and ZEONEXmanufactured by Zeon Corporation, and ARTON manufactured by JSR) such ashomopolymer or copolymer resins of norbornene derivatives,vinylmonomers, or the like, resins obtained by ring-opening metathesispolymerization of norbornene derivatives, and hydrogenation productsthereof; olefin-maleimide resins (for example, TI-PAS manufactured byTosoh) such as copolymers of ethylene and maleimide; polyester resins(for example, O-PET manufactured by Kanebo) such as polyesters obtainedby polycondensation of bisphenols (e.g. bisphenol A,bis(4-(2-hydroxyethoxy)phenyl)fluorene) or diols (e.g. diethyleneglycol) with phthalic acids (e.g. terephthalic acid, isophthalic acid)or aliphatic dicarboxylic acids; polyethersulfone resins, polyarylateresins, polyvinyl acetal resins, polyethylene resins, polypropyleneresins, polystyrene resins, polyamide resins, silicone resins, andfluorine resins, as well as rubbery resins such as natural rubber andEPDM.

The thermoplastic resin may contain a carbon-carbon double bond reactivewith a SiH group or/and a SiH group in the molecule. In view of highertoughness of a cured product to be obtained, the thermoplastic resinpreferably contains at least one carbon-carbon double bond reactive witha SiH group or/and SiH group per molecule on average.

The thermoplastic resin may contain other crosslinkable groups. Examplesof such crosslinkable groups include an epoxy group, amino group,radical-polymerizable unsaturated groups, carboxyl group, isocyanategroup, hydroxyl group, and alkoxysilyl groups. In view of higher thermalresistance of a cured product to be obtained, the thermoplastic resinpreferably contains at least one crosslinkable group per molecule onaverage.

Although the molecular weight of the thermoplastic resin is notparticularly limited, the number average molecular weight of thethermoplastic resin is preferably 10,000 or less, and more preferably5000 or less, in view of better compatibility with the component (A) andthe component (B). Meanwhile, the number average molecular weight of thethermoplastic resin is preferably 10,000 or more, and more preferably100,000 or more, in view of higher toughness of a cured product to beobtained. The molecular weight distribution is also not particularlylimited, and is preferably 3 or less, more preferably 2 or less, andstill more preferably 1.5 or less from the viewpoint that the viscosityof the mixture tends to be low, and thus the moldability tends to bebetter.

The amount of the thermoplastic resin added is not particularly limited.The minimum amount of the thermoplastic resin is preferably 5% byweight, and more preferably 10% by weight, of the whole curable resincomposition, while the maximum amount is preferably 50% by weight, andmore preferably 30% by weight, of the whole curable resin composition.If the addition amount is smaller, a cured product to be obtained tendsto be brittle. If the addition amount is larger, the thermal resistance(elastic modulus at high temperatures) tends to be low.

The thermoplastic resin may be used alone, or a plurality thereof may beused in combination.

The thermoplastic resin may, for example, be homogeneously dissolved inthe component (A) or/and the component (B) prior to mixing, or becrushed into particles prior to mixing, or be dissolved in a solventprior to mixing, for dispersion. In view of higher transparency of acured product to be obtained, the thermoplastic resin is preferablyhomogeneously dissolved in the component (A) or/and the component (B)prior to mixing. In this case, the thermoplastic resin may be directlydissolved in the component (A) or/and the component (B). Alternatively,the thermoplastic resin may be homogeneously mixed using a solvent orthe like, and the solvent may then be removed so as to give ahomogeneous dispersion or/and mixture.

In the case of dispersing the thermoplastic resin, various averageparticle sizes may be employed; however, the minimum average particlesize is preferably 10 nm, and the maximum average particle size ispreferably 10 μm. The particle system may have a distribution, and mayeither be monodispersed or have a plurality of peak particle sizes. Fromthe viewpoint that the viscosity of the curable resin composition tendsto be low, and thus the moldability tends to be better, the coefficientof variation of the particle size is preferably 10% or less.

(Anti-Aging Agents)

An anti-aging agent may be added in the curable resin composition of thepresent invention. Examples of the anti-aging agent include, in additionto anti-aging agents commonly used such as hindered phenol anti-agingagents, citric acid, phosphoric acid, and sulfur anti-aging agents.

Examples of the hindered phenol anti-aging agents include Irganox 1010available from Ciba Specialty Chemicals, and other various agents.

Examples of the sulfur anti-aging agents include mercaptans, mercaptansalts, sulfides including sulfide carboxylic acid esters and hinderedphenol sulfides, polysulfides, dithiocarboxylic acid salts, thioureas,thiophosphates, sulfonium compounds, thioaldehydes, thioketones,mercaptals, mercaptols, monothio acids, polythio acids, thioamides, andsulfoxides.

These anti-aging agents may be used alone, or two or more kinds thereofmay be used in combination.

(Radical Inhibitor)

A radical inhibitor may be added in the curable resin composition of thepresent invention. Examples of the radical inhibitor include phenolicradical inhibitors such as 2,6-di-tert-butyl-4-methylphenol (BHT),2,2′-methylene-bis(4-methyl-6-tert-butylphenol), andtetrakis(methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)methane;and aminic radical inhibitors such as phenyl-β-naphthylamine,α-naphthylamine, N,N′-di-sec-butyl-p-phenylenediamine, phenothiazine andN,N′-diphenyl-p-phenylenediamine.

These radical inhibitors may be used alone, or two or more kinds thereofmay be used in combination.

(Ultraviolet Absorber)

An ultraviolet absorber may be added in the curable resin composition ofthe present invention. Examples of the ultraviolet absorber include2(2′-hydroxy-3′,5′-di-tert-butylphenyl)benzotriazole, andbis(2,2,6,6-tetramethyl-4-piperidine)sebacate.

These ultraviolet absorbers may be used alone, two or more kinds thereofmay be used in combination.

(Solvent)

The curable resin composition of the present invention may be dissolvedin a solvent before use. Usable solvents are not particularly limited,and specific examples thereof include hydrocarbon solvents such asbenzene, toluene, hexane and heptane; ether solvents such astetrahydrofuran, 1,4-dioxane, 1,3-dioxolane and diethyl ether; ketonesolvents such as acetone, methyl ethyl ketone, and methyl isobutylketone; and halogen solvents such as chloroform, methylene chloride and1,2-dichloroethane.

As the solvent, toluene, tetrahydrofuran, 1,3-dioxolane, and chloroformare preferred.

Although various amounts of the solvent may be used, the minimum amountis preferably 0.1 mL, and the maximum amount is preferably 10 mL, per gof the curable resin composition used. If the amount is smaller, theeffects of the solvent, such as reduction in viscosity, are difficult toobtain, while if the amount is larger, problems such as thermal crackingdue to the solvent remaining in the materials tend to occur. Moreover,such a larger amount is disadvantageous in cost, thereby lowering theindustrial utility value.

The solvent may be used alone, or two or more thereof may be used as amixed solvent.

(Additives for Light-Emitting Diode)

Furthermore, the curable resin composition of the present invention maycontain additives for improving various properties of light-emittingdiodes as needed. Examples of the additives include: phosphors which,when they absorb light from light-emitting elements, emitlong-wavelength fluorescent light, such as cerium-dopedyttrium-aluminum-garnet phosphors; colorants which absorb specificwavelengths, such as blueing agents; diffusing materials for diffusinglight, such as titanium oxide, aluminum oxide, melamine resin, CTUguanamine resin, and benzoguanamine resin; and heat conductive fillersincluding metal oxides such as aluminosilicate, and metal nitrides suchas aluminum nitride and boron nitride.

The additives for improving the properties of light-emitting diodes maybe contained uniformly or with a concentration gradient.

(Mold Release Agent)

In order to improve the mold releasability during molding, various moldrelease agents may be added in the curable resin composition of thepresent invention.

Example of the mold release agents include the component (G) explainedabove, and waxes. Examples of the waxes include natural waxes, syntheticwaxes, oxidized or nonoxidized polyolefins, and polyethylene waxes.

Here, it is better not to use the mold release agent in the case wheresufficient moldability can be ensured without addition of the moldrelease agent.

(Other Additives)

Other additives such as colorants, flame retardants, flame retardantpromoters, surfactants, antifoaming agents, emulsifiers, levelingagents, cissing inhibitors, ion trapping agents such as antimony-bismuthcompounds, thixotropic agents, tackifiers, storage stability improvers,antiozonants, photostabilizers, thickeners, plasticizers, reactivediluents, antioxidants, thermal stabilizers, electricalconductivity-imparting agents, antistatic agents, radiation blockers,nucleating agents, phosphorus-based peroxide decomposers, lubricants,pigments, metal deactivators, thermal conductivity-imparting agents andproperty modifiers may be added in the curable resin composition of thepresent invention as long as they do not impair the objects and effectsof the present invention.

(B-Staging)

With regard to the curable resin composition of the present invention,ingredients including the components and additives may be used as theyare, or may be used after partially reacted (B-staged) by heating or thelike. B-staging enables viscosity adjustment and adjustment ofmoldability during transfer molding. Moreover, B-staging has an effectin further suppressing shrinkage on curing.

(Properties of Curable Resin Composition)

As the curable resin composition of the present invention, compositionsformed from various combinations as mentioned above can be used. In viewof good moldability during transfer molding or the like, curable resincompositions having fluidity at temperatures of 150° C. or lower arepreferred.

The curability of the curable resin composition may be appropriatelyset. In view of short molding cycle, the gelation time at 120° C. ispreferably 120 seconds or shorter, and more preferably 60 seconds orshorter. The gelation time at 150° C. is preferably 60 seconds orshorter, and more preferably 30 seconds or shorter. The gelation time at100° C. is preferably 180 seconds or shorter, and more preferably 120seconds or shorter.

The above gelation time is measured as follows. An aluminum foil havinga thickness of 50 μm is placed on an electric hot plate set to apredetermined temperature, and 100 mg of a curable resin composition isput on the foil. Then, the time thereafter until the curable resincomposition is gelated is measured and determined as the gelation time.

In the production process using the curable resin composition, from theviewpoint that processing problems due to formation of voids in thecurable resin composition and outgassing from the curable resincomposition are unlikely to occur, the composition preferably shows aweight loss during curing of at most 5% by weight, more preferably atmost 3% by weight, and still more preferably at most 1% by weight.

The weight loss during curing is determined as follows. A sealant in anamount of 10 mg is heated from room temperature to 150° C. at atemperature increase rate of 10° C./min by using a thermogravimetricanalyzer, and then the ratio of the weight lost to the initial weight isdefined as the weight loss.

From the viewpoint that the curable resin composition is unlikely tocause a problem of silicone contamination when used for electronicmaterials, volatiles from the curable resin composition in this casepreferably have a Si atom content of 1% or less.

(Properties of Cured Product)

In view of good thermal resistance, a cured product obtained by curingthe curable resin composition preferably has a Tg of at least 100° C.,and more preferably at least 150° C.

This Tg is determined as follows. A tan δ peak temperature obtained in adynamic viscoelasticity measurement (using DVA-200 produced by ITKeisoku Seigyo) with a 3 mm×5 mm×30 mm prismatic sample under theconditions of: tensile mode; measurement frequency of 10 Hz; strain of0.1%; static/dynamic load ratio of 1.5; and temperature increase rate of5° C./min is defined as Tg.

In addition, from the viewpoint that problems such as ion migration areless likely to occur to a lead frame or the like, and the reliability isimproved, the content of ions extracted from the cured product ispreferably less than 10 ppm, more preferably less than 5 ppm, and stillmore preferably less than 1 ppm.

In this case, the content of extracted ions is determined in thefollowing manner. Cut pieces of a cured product (1 g) are put togetherwith 50 mL of ultrapure water into a Teflon (registered trademark)container, and the container is then sealed and treated at 121° C. and 2atm for 20 hours. The obtained extract is analyzed by ICP massspectrometry (using HP-4500 produced by Yokogawa Analytical Systems),and the obtained values of the contents of Na and K are converted intoconcentrations in the cured product used. Meanwhile, the same extract isanalyzed by ion chromatography (using DX-500 produced by Dionex; column:AS12-SC), and the obtained values of the contents of Cl and Br areconverted into concentrations in the cured product used. The contents ofNa, K, Cl and Br in the cured product thus obtained are summed and thesum is defined as the content of extracted ions.

The linear expansion coefficient of the cured product is notparticularly limited; however, in terms of higher adhesion to metal suchas a lead frame or ceramics or the like, the average linear expansioncoefficient between 23° C. and 150° C. is preferably at most 30 ppm,more preferably at most 20 ppm, and still more preferably at most 10ppm.

Preferably, a cured product of the curable resin composition of thepresent invention has a spectral reflectance of 80R % or more at 420 nm,440 nm, and 460 nm, and has a spectral reflectance retention rate([spectral reflectance after thermal resistance test]/[initial spectralreflectance]×100) of 90% or more after a thermal resistance test at atemperature of 180° C. for 72 hours.

The spectral reflectance of the cured product is determined as follows.

Spectral reflectances at wavelengths of 400 nm to 700 nm (20 nminterval) are measured using a micro spectrocolorimeter (VSS400 producedby NIPPON DENSHOKU INDUSTRIES CO., LTD). Here, an average of valuesmeasured at arbitrary four points (measurement area: 0.1 mmφ) on theupper surface of the package is defined as the measured value at eachwavelength.

In view of higher light extraction efficiency of light-emitting diodes,the spectral reflectance is preferably 75% or more, and more preferably80% or more, in a wavelength range of 420 nm to 700 nm.

Also, the retention rate of a spectral reflectance after a thermalresistance test (for example, test with heating at 180° C. in an ovenfor 72 hours) to an initial spectral reflectance is determined accordingto the following equation:Retention rate (%)=(spectral reflectance after thermal resistancetest)/(initial spectral reflectance)×100.

In view of high reliability in use for electronic materials, theretention rate is preferably 80% or more, more preferably 85% or more,and still more preferably 90% or more.

A surface of a molded article formed by curing the curable resincomposition of the present invention preferably has a light reflectanceat a wavelength of 470 nm of 90% or more, more preferably 95% or more,still more preferably 97% or more, and particularly preferably 99% ormore.

The light reflectance of the surface can be measured as follows.

A void-free molded article having a thickness of 0.5 mm is prepared bypress-molding under a predetermined temperature condition using a PETfilm as a mold release film. The obtained molded article is subjected topredetermined post-curing as necessary. The total reflection at awavelength of 470 nm of the resulting molded article is measured using aspectrophotometer equipped with an integrating sphere to determine thelight reflectance.

(Curable Resin Composition Tablet)

The curable resin composition of the present invention may be formedinto curable resin composition tablets when it contains at least thecomponent (F) in addition to the components (A) to (E).

Specifically, the curable resin composition tablet characteristicallycontains the components (A) and (B), at least one of which is a liquidhaving a viscosity of at most 50 Pa·s at a temperature of 23° C., thecomponent (C) for curing the components (A) and (B), the components (E)and (F), which are both powder, as well as the component (D). Regardingthe curable resin composition tablet, the whole curable resincomposition becomes flowable when the viscosities of the components (A)and (B) are reduced at high temperatures. When heating is furthercontinued, a curing reaction proceeds to allow molding into desiredshapes.

The molding method is not particularly limited, and methods generallyemployed for molding curable resin compositions, such as transfermolding and compression molding, may be used. In such molding methods,if the curable resin composition as a material is in the form of pasteor clay, a given shape cannot be maintained so that mutual adhesion,integration, or deformation occurs. Thus, it is very difficult tomeasure or transfer the curable resin composition, and supply it to amolding machine. In contrast, if the curable resin composition is in atablet form, it can be easily measured, transferred, or supplied to amolding machine and also allows automation, which significantlyincreases productivity. The tablets herein refer to solid bodies whicheach maintain a given shape at room temperature, do not practicallychange in shape with time, and do not adhere to or integrate one anotherwhen contacted to one another.

The shape of the tablet of the present invention is not particularlylimited, and examples thereof include a cylindrical shape, a prismaticshape, a disk shape, a spherical shape, and the like. A cylindricalshape that is common for transfer molding is preferred.

The total ratio (hereinafter, also referred to as filling proportion) ofthe component (E) and the component (F) is preferably 70% to 95% byweight of the curable resin composition tablet of the present invention.The ratio between the component (E) and the component (F) in the fillingproportion is not particularly limited, and may be freely set.

In the case of the filling proportion of not more than 70% by weight,the following problems may occur: a cured product to be obtained has anexcessively high coefficient of thermal expansion, leading to changes inthe size of the molded article; or the resulting curable resincomposition is in the form of hard paste or clay so that it cannot beformed into tablets. In the case of the filling proportion of not lessthan 95% by weight, the viscosity at high temperatures may be too high,deteriorating the moldability, or tablets to be obtained may be toobrittle.

In the curable resin composition of the present invention, in the casewhere at least one of the component (A) and the component (B) is liquidat normal temperature, the curable resin composition tends to be in theform of paste or clay when the filling proportion is low. In this case,although the curable resin composition cannot be formed into tablets, ittends to have better moldability at high temperatures. In contrast, inthe case of high filling proportion, the curable resin composition tendsto be in the form of flake or powder due to a low amount of flowingcomponents. These forms can be pressed into tablets by compression;however, they tend to have poor fluidity at high temperatures, leadingto lower moldability. Conventionally, it has been difficult to achieveboth formability into tablets and moldability by simply increasing thefilling proportion.

However, the inventors of the present invention have found that it ispossible for the curable resin composition of the present invention toensure both formability into tablets and moldability if particles havinga size of 12 μm or less account for 40% by volume or more of the totalpowder of the component (E) and the component (F).

The reason is presumably thought as follows. In a mixed system ofliquids and particles, the liquid components are supposed to cover thesurface of the particles, and excess liquid components remaining aftercovering all the particles are considered to contribute to deformation.Hence, even when the filling proportion is the same, the larger theproportion of small particles, the greater the total surface area, andin turn, the larger amount of the liquid components is required forcovering. This is thought to be why deformation tends not to occur.Since the viscosity of liquid significantly decreases at hightemperatures, changes in fluidity at high temperatures are small whenthe proportion of small particles varies. At low temperatures, on theother hand, since the viscosity is high, a composition containing alarge proportion of small particles is thought to fail to flow like apaste or clay form, and therefore have a flake or powder form.

In other words, by increasing the proportion of small particles inparticles, it is possible to harden a curable resin composition atnormal temperature while maintaining its fluidity obtainable at hightemperatures. This finding is not obvious from the literatures (JP-A2008-112977, JP-A 2009-155415) teaching the use of epoxy resin orsilicone resin which are solid at normal temperature, or from PatentLiterature 3 which does not teach the particle size distribution butonly describes the average particle size.

(Semiconductor Package)

The semiconductor package herein refers to a member provided in order tosupport and immobilize or/and protect a semiconductor element or/and anexternal lead-out electrode or the like. The semiconductor package maybe one not directly covering a semiconductor element but supporting andimmobilizing an external lead-out electrode or the like, or may be oneforming a periphery or bottom of a semiconductor element, such asreflectors of light-emitting diodes.

Examples of the semiconductor element in this case include varioussemiconductor elements, for example, integrated circuits such as ICs andLSIs, elements such as transistors, diodes and light-emitting diodes,and light-receiving elements such as CCDs.

The form of the semiconductor package is not particularly limited. Theeffects of the present invention tend to be better achieved particularlyif the semiconductor package substantially has a form (MAP type) inwhich resin is formed on one surface of metal.

In the case where, for example, the semiconductor package of the presentinvention does not directly cover a semiconductor element as mentionedearlier, a sealant may also be used for sealing. Examples of the usablesealant include conventionally used sealing resins such as epoxy resin,silicone resin, acryl resin, urea resin, and imido resin. Moreover,sealants made of curable resin compositions each containing an aliphaticorganic compound having at least two carbon-carbon double bonds reactivewith SiH groups per molecule, a compound containing at least two SiHgroups per molecule, and a hydrosilylation catalyst, as proposed in JP-A2002-80733 and JP-A 2002-88244, may be used. Use of such a sealant ispreferred from the viewpoint that higher adhesion to the package resinis achieved, and that an effect of the present invention, high lightresistance, is remarkably shown due to high transparency. Also, sealingcan be carried out by hermetic sealing by covering with glass or thelike without any resin sealant.

Furthermore, a lens may also be used in the case of light-emittingdiodes, light-receiving elements and the like. It is also possible tomold a sealant into a lens shape so that the sealant functions as lens.

(Molding Method)

With regard to the molding method of the semiconductor package accordingto the present invention, various methods are applicable. For instance,various molding methods generally used for thermoplastic resins orthermosetting resins (e.g. epoxy resin, silicone resin) may be used,such as injection molding, transfer molding, RIM molding, castingmolding, press molding, and compression molding. Of these, transfermolding is preferred from the viewpoint that the molding cycle isshorter and the moldability is better. Although the molding conditions,for example the molding temperature, can be appropriately set, themolding temperature is preferably not lower than 100° C., morepreferably not lower than 120° C., and still more preferably not lowerthan 150° C., in terms of more rapid curing, shorter molding cycle, andbetter moldability. It is also optional to carry out post-curing(after-cure) as needed after molding by the aforementioned variousmethods. Post-curing tends to lead to higher thermal resistance.

The molding may be performed at a constant temperature, or may beperformed while the temperature is changed in multiple steps orcontinuously as needed. Rather than a reaction at a constanttemperature, a reaction at temperatures increasing in multiple steps orcontinuously is preferred from the viewpoint that distortion-free,homogeneous cured products are easily obtained. On the other hand, fromthe viewpoint that the molding cycle can be shortened, curing at aconstant temperature is preferred.

Although various curing times may be employed, relatively a long timereaction at low temperatures is preferred rather than a short timereaction at high temperatures, from the viewpoint that distortion-free,homogeneous cured products are easily obtained. On the other hand, fromthe viewpoint that the molding cycle can be shortened, a short timereaction at high temperatures is preferred.

Various pressures during molding may be employed as needed, and moldingcan be carried out under ordinary pressure, high pressure, or reducedpressure. Curing under reduced pressure is preferred from the viewpointthat formation of voids can be suppressed, better filling property isachieved, and it is easy to remove possible volatiles. Curing underincreased pressure is preferred from the viewpoint that cracks in themolded article can be prevented.

(Applications of Light-Emitting Diode)

The semiconductor of the present invention can be used in variousconventionally known applications. Specifically, it can be used inapplications including LSIs such as Logic and Memory LSIs, varioussensors, and light-emitting or receiving devices. Moreover, in the casewhere the semiconductor is a light-emitting diode, it can also be usedin various conventionally known applications. Specifically, it can beused in applications including backlights for liquid crystal displaydevices and the like, lighting devices, sensor light sources, vehicleinstrument light sources, signaling lights, indicator lights, indicatingdevices, light sources of planar light emitters, displays, ornaments,various lights, and the like.

(Warpage)

In the case where the curable resin composition of the present inventionis molded on one surface of a lead frame for light-emitting diodes toform a package, a warpage of the package is preferably at most ±1.0 mm.

The warpage is measured based on a method for measuring the maximumwarpage described in JIS C 6481. Specifically, a semiconductor packageis vertically hung at the center of one side thereof, and a straightedge ruler is applied in parallel with the side. The straight edge ruleris further applied on a concave surface of the semiconductor package.Using a metal rule, the largest distance between the straight edge rulerand the substrate surface of the semiconductor package is measured in mmunit. In the case where the resin is molded on the concave surface ofthe semiconductor package, the largest distance between the straightedge ruler and the resin surface formed on the semiconductor package ismeasured in mm unit using the metal rule. Then, a value obtained bysubtracting the thickness of the resin from the measured value isrounded in mm unit.

The same measurements are successively performed on other sides, and themaximum value among the obtained largest distances is defined aswarpage. Here, the semiconductor package described in (Molding method)in EXAMPLES was used for the measurement of warpage.

EXAMPLES

Examples and comparative examples of the present invention are shownbelow; however, the present invention is not limited thereto.

Synthesis Example 1

A stirrer, a drip funnel and a condenser tube were set in a four-necked5-L flask. To this flask were added 1,800 g of toluene and 1,440 g of1,3,5,7-tetramethylcyclotetrasiloxane, which were then heated andstirred in an oil bath at 120° C. A mixed solution of 200 g of triallylisocyanurate, 200 g of toluene and 1.44 mL of a xylene solution(platinum content: 3% by weight) of platinum-vinylsiloxane complex wasadded dropwise over 50 minutes. The obtained solution was heated andstirred as it was for 6 hours, and then unreacted1,3,5,7-tetramethylcyclotetrasiloxane and toluene were removed in vacuo.It was found by ¹H-NMR measurement that the product had the followingstructure obtained by a reaction of part of the SiH groups of1,3,5,7-tetramethylcyclotetrasiloxane with triallyl isocyanurate.

Synthesis Example 2

A 2-L autoclave was charged with 720 g of toluene and 240 g of1,3,5,7-tetramethylcyclotetrasiloxane, which, after the gas phase wasreplaced by nitrogen, were heated and stirred at a jacket temperature of50° C. A mixed solution of 171 g of allyl glycidyl ether, 171 g oftoluene and 0.049 g of a xylene solution (platinum content: 3% byweight) of platinum-vinylsiloxane complex was added dropwise over 90minutes. After completion of the dropwise addition, the jackettemperature was raised to 60° C., a reaction was allowed to proceed for40 minutes, and the reaction rate of allyl groups was verified to be atleast 95% by ¹H-NMR. A mixed solution of 17 g of triallyl isocyanurateand 17 g of toluene was added dropwise, then, the jacket temperature wasraised to 105° C., and a mixed solution of 66 g of triallylisocyanurate, 66 g of toluene and 0.033 g of a xylene solution (platinumcontent: 3% by weight) of platinum-vinylsiloxane complex was addeddropwise over 30 minutes. Four hours after completion of the dropwiseaddition, the reaction rate of allyl groups was verified to be at least95% by ¹H-NMR, and the reaction was then stopped by cooling. The ratioof unreacted 1,3,5,7-tetramethylcyclotetrasiloxane was 0.8%. Unreacted1,3,5,7-tetramethylcyclotetrasiloxane, toluene, and byproducts of allylglycidyl ether ((cis and trans) products via internal rearrangement ofthe vinyl group of allyl glycidyl ether) were removed in vacuo so as tobe present in at most 5,000 ppm in total, so that a colorlesstransparent liquid was obtained. It was found by ¹H-NMR measurement thatthe product was a compound obtained by a reaction of part of the SiHgroups of 1,3,5,7-tetramethylcyclotetrasiloxane with allyl glycidylether and triallyl isocyanurate, and having the following structure onaverage.

Formulation Examples 1 to 4

Components were mixed in the proportions shown in Table 1 to preparecompositions A to D.

TABLE 1 Formulation Formulation Formulation Formulation Example 1Example 2 Example 3 Example 4 Composition A Composition B Composition CComposition D Component Triallyl isocyanurate 40.2 g  2.9 g 19.4 g  58.3g (A) Diallyl monoglycidyl 28.1 g 13.9 g 41.71 g isocyanurate ComponentProduct of Synthesis Example 1 59.8 g 29.3 g 88.21 g (B) Product ofSynthesis Example 2 69.0 g 37.4 g 112.48 g  Component Xylene solution ofplatinum- 0.050 g  0.018 g  0.029 g   0.09 g (C) vinylsiloxane complexCuring 1-Ethynyl-1-cyclohexanol  0.3 g  0.1 g  0.2 g  0.49 g retardant

Examples 1 to 5 and Comparative Example 1

Components were mixed in the proportions shown in Table 2 to preparecurable resin compositions according to the present invention.

Measurement Example 1

The curable resin compositions were press-molded at a temperature of150° C. Molded articles thus obtained were subjected to post-curing inan oven at 150° C. for one hour and at 180° C. for 0.5 hours. The linearexpansion coefficients of the resulting samples were measured bythermomechanical analysis (TMA). TMA measurement method was as follows.

The tablet-shaped molded samples with an inner size of 20×20×4.0 mm (inthickness) were cut into a size of 20×10×4.0 mm with a diamond cutter.Using a thermal analyzer (TMA 4000SA, produced by BRUKER), changes inthe size of the sample in the 20 mm-direction were measured when thetemperature was raised to 280° C. at a temperature increase rate of 5°C./min, held for 20 minutes, and cooled to room temperature incompression mode. Tg was defined as the onset of change in the slope ofa chart during heating, and the linear expansion coefficient α1 nothigher than the Tg and the linear expansion coefficient α2 not lowerthan the Tg were determined.

TABLE 2 Comparative Example 1 Example 2 Example 3 Example 4 Example 5Example 1 Composition Composition A 50 50 Composition B 50 50 100Composition C 50 Component (D) PVD-2331* 50 50 50 50 27 Component (F)Titanium oxide (PC-3**) 300 300 239 Titanium oxide (R-820**) 250 250 250Component (E) Silica (MSR-3500***) 550 710 550 710 550 Silica(MSR-2212-TN***) 557 Linear expansion coefficient (average linear 6.9ppm 5.0 ppm 16.1 ppm 9.1 ppm 11.0 ppm 33.0 ppm expansion coefficientbetween 23° C. and 150° C.) Values of the components are shown asrelative percentages by weight. In the Examples and Comparative Example,components in predetermined proportions were weighed so as to be 100 gin total, and homogeneously mixed to prepare curable compositions.*produced by Gelest, linear methyl phenyl silicone containing a vinylgroup at both terminals (the amount of phenyl groups is 22 to 25 mol %of the total substituents) **produced by Ishihara Sangyo Kaisha, Ltd.***produced by Tatsumori Ltd.

As shown in Table 2, the curable resin compositions of the presentinvention resulted in small linear expansion coefficients.

The curable resin composition in Example 5 was subjected to transfermolding with a silver-plated copper lead frame to give a package havinga form (MAP type) in which resin is formed on one surface of metal. Themolding was performed under the following conditions.

-   Molding temperature: 170° C.-   Molding time: 180 seconds-   Molding pressure: 7.8 to 13.7 MPa

Curing was then performed at 180° C. for one hour after the molding.

Measurement Example 2

The package of the curable resin composition prepared by the abovemolding and packages of Comparative Examples 2 to 6 were measured forthe spectral reflectance at wavelengths of 400 nm to 700 nm (20 nminterval) by using a micro spectrocolorimeter (VSS400 produced by NIPPONDENSHOKU INDUSTRIES CO., LTD). Here, an average of values measured atarbitrary four points (measurement area: 0.1 mmφ) on the upper surfaceof the package was defined as the measured value at each wavelength.Also, the retention rate of a spectral reflectance after a thermalresistance test (test with heating at 180° C. in an oven for 72 hours)to an initial spectral reflectance was determined according to thefollowing equation:Retention rate (%)=(spectral reflectance after thermal resistancetest)/(initial spectral reflectance)×100.

Table 3 shows the results of spectral reflectance.

TABLE 3 Comparative Comparative Comparative Comparative ComparativeExample 5 Example 2 Example 3 Example 4 Example 5 Example 6 Spectral 420nm Initial 86 83 58 65 63 72 reflectance (R %) After thermal 85 60 10 166 14 resistance test (at 180° C. for 72 hours) Retention rate (%) 99 7317 25 9 20 440 nm Initial 94 89 64 71 67 76 After thermal 92 65 12 21 716 resistance test (at 180° C. for 72 hours) Retention rate (%) 98 74 1929 10 21 460 nm Initial 95 90 68 75 70 79 After thermal 93 69 15 26 8 17resistance test (at 180° C. for 72 hours) Retention rate (%) 99 76 22 3412 22 Comparative Example 2: Package LED equipped with EVERLEDS producedby Panasonic Corporation Comparative Example 3: NSSM009B produced byNichia Corporation Comparative Example 4: XW1147B produced by StanleyComparative Example 5: LBG6SP-V2BB-35-1 produced by OSRAM ComparativeExample 6: LWG6SP-CBEA-5K8L-1 produced by OSRAM

FIGS. 1 and 2 show the initial spectral reflectances and spectralreflectances after the thermal resistance test at 180° C. in Example 5and Comparative Examples 1 and 2.

Examples 6 to 8, Comparative Examples 7 to 9

Table 4 shows the formulation proportions of the components of thecurable resin compositions. The following materials were used for thecomponent (D), the component (E), and the component (F).

(Component (D))

PDV2331 (diphenyl dimethyl silicone containing a vinyl group at bothterminals thereof, produced by Gelest)

(Component (E))

Spherical silica (produced by TATSUMORI LTD.; MSR-3500; specificgravity: 2.2; average particle size: 36.5 μm; content of particleshaving a size of 12 μm or less: 19%)

Spherical silica (produced by TATSUMORI LTD.; MSR-2212-TN; specificgravity: 2.2; average particle size: 24.8 μm; content of particleshaving a size of 12 μm or less: 28%)

Spherical silica (produced by Admatechs; Admafine SO-C2; specificgravity: 2.2; average particle size: 0.5 μm; content of particles havinga size of 12 μm or less: 100%)

(Component (F))

Titanium oxide (produced by ISHIHARA SANGYO KAISHA, LTD.; Tipaque PC-3;rutile type; specific gravity: 4.2; chloride process; organic compoundon surface: Al, Si; polymethylhydrogensiloxane; average particle size:0.21 μm; content of particles having a size of 12 μm or less: 100%)

TABLE 4 Comparative Comparative Comparative Example 6 Example 7 Example8 Example 7 Example 8 Example 9 wt % vol % wt % vol % wt % vol % wt %vol % wt % vol % wt % vol % Composition A 3.4 6.6 2.7 5.3 2.4 4.9 7.816.0 9.0 17.0 Composition B 3.8 7.4 3.1 6.1 2.8 5.6 8.1 16.0 Component(F) Titanium PC-3 27.8 15.0 27.4 15.0 27.1 15.0 20.9 11.2 27.0 15.0 25.014.0 oxide Component (E) Spherical MSR-3500 61.2 62.5 52.0 54.0 silicaMSR-2212-TN 63.8 66.5 64.9 68.0 71.0 72.7 65.2 69.0 SO-2C 14.0 15.0Component (D) PDV-2331 3.8 8.5 3.1 7.1 2.8 6.5 Appearance of resin PasteTablet Tablet Tablet Tablet Tablet Warpage before PMC <1.0 <1.0 <1.0 0.05.0 3.0 Warpage after PMC 1.0 1.0 1.0 5.0 5.0< 3.0< Reflectance at 470nm (%) (after PMC) 100 100 100 100 100 100 PMC: Post-curing condition(Formulation of Curable Resin Composition)

A preliminarily-mixed powder of the component (F) and the component (E)was added little by little to a separately-prepared mixed solution ofthe compositions A and B and the component (D), and then mixed andkneaded. In the case where the resulting curable resin composition wasin a paste form, the composition was homogenized by mixing and kneadingwith a stirring rod. In the case of a clay form, it was homogenized byrepetition of flattening with a round bar-shaped jig, folding and thenflattening again. In the case of a flake or powder form, it washomogenized by grinding in a mortar.

(Forming into Tablet)

In the case where the prepared curable resin composition was in a flakeor powder form, it was compressed into tablets with a tableting jigincluding metal mortars and pestles.

Table 4 shows the final formulation proportions of the components of thecurable resin compositions and the appearance of the resins.

(Molding Method)

The curable resin compositions of Examples 6 to 8 and ComparativeExamples 7 to 9 shown in Table 4 were each molded on one surface of alead frame for light-emitting diodes to prepare a package forlight-emitting diodes of MAP type (a type of semiconductor packagessubstantially having a form in which resin is formed on one surface ofmetal).

An Ag-plated copper lead frame having a size of 50 mm in length, 55 mmin width, and 0.25 mm in thickness is prepared.

The MAP after molding includes a total of 180 pieces of reflectors withvertical 15 rows and horizontal 12 rows. In each reflector, the uppersurface has φ 2.1 mm, the bottom surface has φ 1.8 mm (taper angle:15°), and the height is 0.55 mm, and an electrode slit having a width of0.20 mm formed of a white compound obtained by curing the curable resincomposition of the present invention is vertically provided at aposition 0.45 mm from the right side along the horizontal diameter. Aspace between the reflectors is 1.1 mm in both of the longitudinal andlateral diameter directions. The lead frame and the die are notparticularly limited as long as a reflector with a lead frame satisfyingthe above requirements can be produced. FIG. 3 shows a conceptualdiagram of the molded article.

The transfer molding was performed using a G-Line manual press producedby Apic Yamada Corporation. The mold clamping force was 30 ton, theinjection pressure was 8 MPa, and the injection rate was 3 mm/s. Anamount of 5.0 g of a white compound was weighed out, formed into acylindrical shape, loaded in a cylinder, and molded. The moldingconditions were a temperature of 150° C. and a time of 5 minutes. Themolded product was subjected to post-curing (after-cure) in a hot airoven at 150° C. for one hour and subsequently at 180° C. for 30 minutes.

(Warpage)

Warpage was measured by the following method based on a method ofmeasuring the maximum warpage described in JIS C 6481. A semiconductorpackage was vertically hung at the center of one side thereof, and astraight edge ruler was applied on a concave surface of thesemiconductor package, in parallel with that side. Using a metal rule,the largest distance between the straight edge ruler and the substratesurface of the semiconductor package was then measured in mm unit. Inthe case where the resin was molded on the concave surface of thesemiconductor package, the largest distance between the straight edgeruler and the resin surface formed on the semiconductor package wasmeasured in mm unit using the metal rule. Then, a value obtained bysubtracting the thickness of the resin from the measured value wasrounded in mm unit. The same measurements were successively performed onother sides, and the maximum value among the measured largest distanceswas defined as warpage. Table 4 shows the measurement results.

Comparison between the examples and the comparative examples revealsthat the addition of the component (D) provided semiconductor packageswith a warpage of at most 1.0 mm.

(Light Reflectance at Wavelength of 470 nm)

The curable resin compositions in Table 4 were press-molded at 150° C.for 5 minutes using a stainless steel (SUS304) rectangular mold with aninner size of 80 mm×50 mm and a thickness of 0.5 mm, and a PET film as amold release film. The produced rectangular plate-shaped press-moldedarticles were post-cured in an oven at 150° C. for one hour and at 180°C. for 0.5 hours. The light reflectance at a wavelength of 470 nm of theobtained molded articles was measured using a spectrophotometer equippedwith an integrating sphere (produced by JASCO Corporation; UV-visiblespectrophotometer V-560). The reflectance was measured using aspectralon plate produced by Labsphere, Inc., as the standard plate.Table 4 shows the measurement results.

Examples 9 to 11

Table 5 shows the formulation proportions of the components of thecurable resin compositions. The materials used are as follows.

(Component (D))

PDV2331 (diphenyl dimethyl silicone containing a vinyl group at bothterminals thereof, produced by Gelest)

(Component (E))

Spherical silica (produced by TATSUMORI LTD.; MSR-3500; specificgravity: 2.2; average particle size: 36.5 μm; content of particleshaving a size of 12 μm or less: 19%)

(Component (F))

Titanium oxide (produced by ISHIHARA SANGYO KAISHA, LTD.; Tipaque CR-60;rutile type; specific gravity: 4.2; chloride process; surface treatment:aluminum compound; average particle size: 0.21 μm; content of particleshaving a size of 12 μm or less: 100%)

Titanium oxide (produced by ISHIHARA SANGYO KAISHA, LTD.; Tipaque PC-3;rutile type; specific gravity: 4.2; chloride process; surface treatment:aluminum compound, silicon compound, organosilicon compound; averageparticle size: 0.21 μm; content of particles having a size of 12 μm orless: 100%)

Titanium oxide (produced by ISHIHARA SANGYO KAISHA, LTD.; Tipaque PF690; rutile type; specific gravity: 4.2; chloride process; surfacetreatment: aluminum compound, silicon compound, organic compound;average particle size: 0.21 μm; content of particles having a size of 12μm or less: 100%)

TABLE 5 Example 9 Example 10 Example 11 Titanium oxide CR-60 PC-3 PF690Surface Inorganic compound Aluminum Aluminum compound Aluminum compoundtreatment compound Silica compound Silica compound Organic compound NoneOrganosilicon Organic compound compound wt % vol % wt % vol % wt % vol %Composition A prepared in 3.4 6.6 3.4 6.6 3.4 6.6 Formulation Example 1Composition B prepared in 3.8 7.4 3.8 7.4 3.8 7.4 Formulation Example 2Component (F) Titanium oxide 27.8 15.0 27.8 15.0 27.8 15.0 Component (E)MSR-3500 61.2 62.5 61.2 62.5 61.2 62.5 Component (D) PDV-2331 3.8 8.53.8 8.5 3.8 8.5

Table 6 shows the final proportions of the components (A), (B), (C),(D), (E), and (F).

TABLE 6 Example 9 Example 10 Example 11 wt % vol % wt % vol % wt % vol %Component (A) 2.5 4.9 2.5 4.9 2.5 4.9 Component (B) 4.6 9.0 4.6 9.0 4.69.0 Component (C) Trace Trace Trace Trace Trace Trace amount amountamount amount amount amount Component (F) 27.8 15.0 27.8 15.0 27.8 15.0Component (E) 61.2 62.5 61.2 62.5 61.2 62.5 Component (D) 3.8 8.5 3.88.5 3.8 8.5 Curing retardant Trace Trace Trace Trace Trace Trace amountamount amount amount amount amount Width of test piece [mm] 7.54 7.477.51 Thickness of test piece [mm] 0.55 0.58 0.71 Area [mm²] 4.18 4.355.33 Maximum load [kgf] 0.20 0.17 0.21 Maximum stress [kPa] 48.8 39.939.2 Light reflectance (%) at a 99 100 100 wavelength of 470 nm(Formulation of Curable Resin Composition)

A preliminarily-mixed powder of the component (F) and the component (E)was added little by little to a separately-prepared mixed solution ofthe compositions A and B and the component (D), and then mixed andkneaded. The resulting curable resin composition was homogenized byrepetition of flattening with a round bar-shape jig, folding and thenflattening again. In the case of a flake or powder form, it washomogenized by grinding in a mortar.

(Preparation of Flat Plate by Heat-Curing of Curable Resin Composition)

The curable resin compositions in Table 5 were press-molded at 150° C.for 5 minutes using a stainless steel (SUS304) rectangular mold with aninner size of 80 mm×50 mm and a thickness of 0.5 mm, and a PET film as amold release film. The produced rectangular plate-shaped press-moldedarticles were post-cured in an oven at 150° C. for one hour and at 180°C. for 0.5 hours so that flat plates were prepared.

(Method of Measuring Strength)

Test pieces each having a length of at least 50 mm but not more than 80mm and a width of approximately 7 mm to 8 mm, and having two oppositesides parallel to each other, were cut out from the prepared flatplates. As shown in FIG. 4, each test piece was set between metalfulcrums having a rectangular-parallelepiped shape with round edges, ina manner that the shape of the test piece between the fulcrums wasrectangular. The width and thickness of the test piece were measured in0.01 mm unit at three points located between the fulcrums, and therespective average values were determined as measurement results. Thearea was calculated from the determined width and thickness of the testpiece. Using a texture analyzer (Ta. Plus, produced by Stable MicroSystems Ltd.), load was applied to the test piece at the center thereofat a rate of 2.0 mm/sec by a pressure wedge made of glass, having aright triangle shape with round edges and having a width of 10 mm. Theload (maximum load) when the test piece broke was measured. An averagevalue of five measurements was determined as a measurement result. Themaximum stress was calculated by dividing the maximum load by the area.

Table 6 shows the measurement results. The results reveal that themaximum load was larger in the case of using titanium oxidesurface-treated with an aluminum compound than in the case of usingtitanium oxide surface-treated with an organosilicon compound or anorganic compound in addition to surface treatment with an aluminumcompound and a silica compound. This is presumably because the titaniumoxide surface-treated only with an aluminum compound as the component(F) has better dispersibility in the curable resin composition.

(Light Reflectance at Wavelength of 470 nm)

The light reflectance at a wavelength of 470 nm of the prepared testpieces was measured using a spectrophotometer equipped with anintegrating sphere (produced by JASCO Corporation; UV-visiblespectrophotometer V-560). The reflectance was measured using aSpectralon plate produced by Labsphere, Inc., as the standard plate.Table 6 shows the measurement results.

Examples 12 to 18

Components were mixed in the proportions shown in Tables 7 and 8 toprepare the curable resin compositions of the present invention.

Measurement Example 1

The curable resin composition (0.5 g) was sandwiched between a SUS 304plate (cold-rolled stainless steel, produced by Taiyu Kizai Co., Ltd.,25×70×0.15 mm) masked with a PET film (25×30×0.15 mm) and a polyimidetape, and a SUS 304 plate (25×50×0.15 mm) formed into a L-shape andhaving punched holes, and then pressed at 5 MPa for 10 seconds at roomtemperature. The resulting product was compressed and cured under a loadof 5 kg for five minutes on a hot plate heated at 170° C. Then, the peelstrength of the resin was measured as follows: while the resulting curedmolded article was placed on a hot plate heated at 170° C., the SUS 304plate of the SUS plate test sample was peeled at a rate of 5 mm/s withone end of the SUS 304 plate held fixed, using a push-pull gauge(DS2-20N: IMADA) attached to the L-bent SUS 304 plate, thereby the peelstrength was measured. Furthermore, the conditions of the peeled surfacewere observed, and breakage of the resin itself was evaluated ascohesive failure (CF), and clean peeling of the resin from both SUSplates was evaluated as interfacial delamination (AF).

TABLE 7 Example 12 Example 13 wt % wt % Composition Composition A 3.43.3 Composition B 3.8 3.7 Component (F) Titanium oxide (PC-3⁽¹⁾) 27.827.3 Component (E) MSR-3500⁽²⁾ 61.1 60.0 Component (D) PDV-2331⁽³⁾ 3.83.7 Component (G) Calcium stearate⁽⁴⁾ 0.2 2.0 Peel force (kg/25 mm) 0.120.18 Failure mode Interfacial Interfacial delamination delamination (AF)(AF) Mold releasability good good ⁽¹⁾produced by Ishihara Sangyo Kaisha,Ltd. ⁽²⁾produced by Tatsumori Ltd. ⁽³⁾produced by Gelest, Linear methylphenyl silicone containing a vinyl group at both terminals (The amountof phenyl groups is mol % of the total substituents.) ⁽⁴⁾produced byWako Pure Chemical Industries

As shown in Table 7, the curable resin compositions of the presentinvention can provide materials which are excellent in moldreleasability.

(Preparation of MAP (Mold Array Package)-Type Reflector with Lead Frame)

MAP-type reflectors with lead frames were prepared using the curableresin compositions of Examples 14 to 18 shown in Table 8 according tothe following method.

An Ag-plated copper lead frame having a size of 50 mm in length, 55 mmin width, and 0.25 mm in thickness is prepared. The MAP after moldingincludes a total of 180 pieces of reflectors with vertical 15 rows andhorizontal 12 rows. In each reflector, the upper surface has φ 2.1 mm,the bottom surface has φ 1.8 mm (taper angle: 15°), and the height is0.55 mm, and an electrode slit having a width of 0.20 mm formed of awhite compound obtained by curing the curable resin composition of thepresent invention is vertically provided at a position 0.45 mm from theright side along the horizontal diameter. A space between the reflectorsis 1.1 mm in both of the longitudinal and lateral diameter directions.The lead frame and die are not particularly limited as long as areflector with a lead frame satisfying the above requirements can beprepared. The form of this molded article is referred to as 3030MAPtype.

The transfer molding was performed using a G-Line manual press producedby Apic Yamada Corporation. The mold clamping force was 30 ton. Theinjection pressure and the injection rate were set to the values shownin Table 8. An amount of 5.0 g of a white compound was weighed out,formed into a cylindrical shape, loaded in a cylinder, and molded whilethe surface of the mold was sprayed with a fluorine mold release agent(spray type) (produced by Daikin Industries, Ltd.; Daifree-GA-7500). Themolding conditions were a temperature of 170° C. and a time of 3minutes. The molded product was subjected to post-curing at 180° C. forone hour.

TABLE 8 Example 14 Example 15 Example 16 Example 17 Example 18Composition Composition A (wt %) 2.7 2.7 2.7 2.7 2.7 Composition B (wt%) 3.1 3.1 3.1 3.1 3.1 Component (F) Titanium oxide (PC-3) (wt %) 63.763.7 63.7 63.7 63.7 Component (E) MSR-2212-TN⁽⁶⁾ (wt %) 27.3 27.3 27.327.3 27.3 Component (D) PDV-2331 (wt %) 3.1 3.1 3.1 3.1 3.1 Component(G) Calcium stearate (wt %) 0.2 0.2 0 0 0 Compound amount (g) 5.5 5.55.5 5.5 5.5 Molding Injection pressure (Mpa) 7.9 7.7 7.7 12 12conditions Injection rate (mm/s) 3 3 3 6 12 Curing Temperature (° C.)170 170 170 170 170 conditions Time (min) 3 3 3 3 3 Post-curingTemperature (° C.) 180 180 180 180 180 conditions Time (min) 60 60 60 6060 Filling rate % 100 100 80 95 98 Warpage Obverse warpage or reverseNone None Reverse Reverse Reverse warpage (mm) warpage 0.5 warpage 0.5warpage 0.5 ⁽⁶⁾produced by Tatsumori Ltd.

As shown in Table 8, in molding of the 3030MAP, the systems in whichcalcium stearate was added showed more favorable MAP filling property,and provided high quality products with almost no warpage. In contrast,the systems in which calcium stearate was not added showed poor fillingproperty, and also provided molded articles with observable warpage.Accordingly, it was found that the addition of the component (G) notonly improves the mold releasability as illustrated in Table 7, but alsocontributes to better resin-filling property, thereby reducing warpageof the molded article.

(Filling Rate)

The filling rate was determined by evaluating the ratio of unfilledarea, with the filling rate of the compound resin fully filled in amolding part being regarded as 100%.

(Evaluation of Warpage)

The MAP product was placed on a flat surface with the molded part up.Warpage of the MAP product was defined as obverse warpage when themolded part seen from a right lateral direction was in a concave shape,and defined as reverse warpage when it was in a convex shape. Withrespect to the degree of warpage, the MAP product was placed on a flatsurface, and the largest distance (mm) among the distances from thesurface to four distant sides was quantified.

Examples 19 to 22

Components in Table 9 were mixed to provide curable resin compositionsaccording to the present invention. If the resulting curable resincomposition was in a paste form, it was homogenized by mixing andkneading with a stirring rod. In the case of a clay form, it washomogenized by repetition of flattening with a round bar-shaped jig,folding and then flattening again. In the case of a flake or powderform, it was homogenized by grinding in a mortar.

TABLE 9 Example 19 Example 20 Example 21 Example 22 wt % vol % wt % vol% wt % vol % wt % vol % Components Composition D 5.25 11.4 6.08 13.96.56 11.4 5.27 11.4 (A) + (B) + (C) Component (D) PDV-2331 2.81 7.1 3.268.6 3.51 7.1 2.82 7.1 Component (E) MSR-2212-TN 58.23 66.1 47.90 57.072.78 66.1 58.41 66.1 Component (F) Zinc oxide (#1)^(a)) 33.51 15.042.56 20.0 Boron nitride (MBN-010T)^(b)) 16.95 15.0 Barium titanate(BT-HP9DX)^(c)) 33.31 15.0 Component (G) Calcium stearate 0.20 0.4 0.200.5 0.20 0.4 0.20 0.4 Initial reflectance (%) at 470 nm 92 94 90 91Reflectance after 180° C. 20 h 92 93 89 89 durability test (%) 85°C./85% RH 92 94 90 91 at 470 nm Metaling (50 MJ) 94 93 88 90^(a))produced by Sakai Chemical Industry Co., Ltd.; average particlesize: 0.6 μm ^(b))produced by Mitsui Chemicals, Inc.; average particlesize: 1 μm ^(c))produced by KCM Corporation Co., Ltd.; average particlesize: 0.662 μm(Preparation of Samples)

The curable resin compositions in Table 9 were press-molded at 170° C.for 3 minutes using a stainless steel (SUS304) rectangular mold with aninner size of 80 mm×50 mm and a thickness of 0.5 mm, and a PET film as amold release film. The prepared rectangular plate-shaped press-moldedarticles were post-cured in an oven at 180° C. for one hour. Theresulting products were cut into a size of 50 mm×25 mm to give samplesfor evaluation.

As a durability test, a thermal resistance test, a light resistancetest, and a constant temperature and humidity test were performed by thebelow-mentioned methods. Here, the light reflectance at a wavelength of470 nm of each sample was measured before the durability test, and themeasured value was defined as initial reflectance.

(Thermal Resistance Test)

The samples prepared as above were aged for 20 hours in a convectionoven (in the air) whose temperature was set to 180° C. Thereafter, thelight reflectance at a wavelength of 470 nm of the aged samples wasmeasured.

(Light Resistance Test: Metaling)

A metaling weather meter (Type “M6T”) produced by Suga Test InstrumentsCo., Ltd. was used. The samples prepared as above were irradiated at ablack panel temperature of 120° C. and an irradiance of 0.53 kW/m² untilthe integrated irradiance reached 50 MJ/m². Thereafter, the lightreflectance at a wavelength of 470 nm of the samples was measured.

(Constant Temperature and Humidity Test: 85° C./85% RH)

A constant low temperature/humidity chamber (LH43-13M) produced byNagano Science Co., Ltd. was used. The samples prepared as above wereaged for 90 hours at a temperature of 85° C. and a humidity of 85% RH.Thereafter, the light reflectance at a wavelength of 470 nm of the agedsamples was measured.

(Light Reflectance at Wavelength of 470 nm)

The light reflectance at a wavelength of 470 nm of the samples beforeand after the durability test was measured using a spectrophotometerequipped with an integrating sphere (produced by JASCO Corporation;UV-visible spectrophotometer V-560). The reflectance was measured usinga Spectralon plate produced by Labsphere, Inc., as the standard plate.Table 9 shows the measurement results.

The invention claimed is:
 1. A semiconductor package which comprises acured resin product of a curable resin composition comprising, asessential components, (A) an organic compound having at least twocarbon-carbon double bonds reactive with SiH groups per molecule whichis free of any siloxane (Si—O—Si) units, or, reaction products of one ormore kinds of compounds selected from the organic compounds having atleast two carbon-carbon double bonds reactive with SiH groups permolecule which are free of any siloxane (Si—O—Si) units, with a compoundcontaining a SiH group (B) a compound containing at least two SiH groupsper molecule, (C) a hydrosilylation catalyst, (D) a silicone compoundhaving at least one carbon-carbon double bond reactive with a SiH groupper molecule, (E) an inorganic filler, and (F) a white pigment, whereinthe component (E) and the component (F) are contained in a total amountof 70% to 95% by weight, wherein the cured resin product furthercomprises a metal, wherein the curable resin composition is molded bytransfer molding.
 2. The semiconductor package according to claim 1,wherein the component (D) is a linear polysiloxane containing a vinylgroup at a terminal thereof.
 3. The semiconductor package according toclaim 1, wherein the component (D) has a weight average molecular weightof at least 1,000 but not more than 1,000,000.
 4. The semiconductorpackage according to claim 1, wherein the component (E) is sphericalsilica.
 5. The semiconductor package according to claim 1, wherein thecomponent (F) has an average particle size of 1.0 μm or less.
 6. Thesemiconductor package according to claim 1, wherein the component (F) istitanium oxide.
 7. The semiconductor package according to claim 6,wherein the component (F) is titanium oxide that is surface-treated withan organosiloxane.
 8. The semiconductor package according to claim 6,wherein the component (F) is titanium oxide that is surface-treated withan inorganic compound.
 9. The semiconductor package according to claim8, wherein the component (F) is surface-treated with an aluminumcompound.
 10. The semiconductor package according to claim 1, whereinthe component (F) is at least one selected from the group consisting ofzinc oxide, zirconium oxide, strontium oxide, niobium oxide, boronnitride, barium titanate, and barium sulfate.
 11. The semiconductorpackage according to claim 1, further comprising (G) a metal soap. 12.The semiconductor package according to claim 11, wherein the component(G) is a metal stearate.
 13. The semiconductor package according toclaim 12, wherein the component (G) is at least one selected from thegroup consisting of calcium stearate, magnesium stearate, zinc stearate,and aluminum stearate.
 14. The semiconductor package according to claim11, wherein the component (G) is contained in an amount of 0.01% to 5%by weight of the whole curable resin composition.
 15. The semiconductorpackage according to claim 1, wherein the component (D) is contained inan amount of 30% by weight or more of the total weight of the component(A) and the component (B).
 16. The semiconductor package according toclaim 1, wherein the component (E) is contained in a total amount of 70%by weight or more of the whole curable resin composition.
 17. Thesemiconductor package according to claim 1, wherein the component (F) iscontained in an amount of 10% by weight or more of the whole curableresin composition.
 18. The semiconductor package according to claim 1,wherein the cured resin product of the curable resin composition has aspectral reflectance of 80 R % or more at 420 nm, 440 nm, and 460 nm,and has a spectral reflectance retention rate ([spectral reflectanceafter thermal resistance test]/[initial spectral reflectance]×100) of90% or more after a thermal resistance test at a temperature of 180° C.for 72 hours.
 19. The semiconductor package according to claim 1,wherein a surface of the cured resin product formed by curing thecurable resin composition has a light reflectance at a wavelength of 470nm of 90% or more.
 20. The semiconductor package according to claim 1,further comprising a lead frame integrally molded with the cured resinproduct.
 21. The semiconductor package according to claim 1, wherein thesemiconductor package substantially comprises a metal and the curedresin product formed on one surface of the metal.
 22. A semiconductorcomponent comprising the semiconductor package according to claim
 1. 23.A light-emitting diode comprising the semiconductor package according toclaim
 1. 24. The semiconductor package according to claim 1, whereinwhen the cured resin product is molded on one surface of a lead framefor light-emitting diodes to form the semiconductor package, and awarpage of the semiconductor package is at most ±1.0 mm.
 25. Thesemiconductor package according to claim 1, wherein the ratio of thenumber (Y) of SiH groups in the component (B) to the number (X) ofcarbon-carbon double bonds in the component (A) is 3≧Y/X≧0.3.